Dangerous heat, mainly in western Japan. Be careful of sudden changes in the weather in the afternoon inland and mountains in the west to eastern Japan.

2025/08/16 07:25

The area around Honshu is covered by tall high pressure systems, and today, the 16th, many areas will be sunny, mainly in western and northern Japan.
In western Japan, strong sunlight will shine brightly, and many days are expected to be extremely hot at 35 C or higher. The temperature rises to 38 C in Yamaguchi City, Kurume City (Fukuoka Prefecture), and Hita City (Oita Prefecture), making it a dangerous heat. Take full precautions against heat stroke.



In the afternoon, the atmosphere conditions are expected to be unstable, mainly in western and eastern Japan. Looking at today's lightning probability forecast, the probability is high, especially inland and mountains in western Japan and eastern Japan, so you'll likely need to be careful of sudden changes in the weather. Locally, there is a risk of heavy rain or thunderstorms with more than 30 mm of lightning per hour, and extremely heavy rain over 50 mm of lightning per hour. In particular, if you are going to leisure activities on mountains or rivers, be careful of changes in the sky and sudden changes in the weather.
Also, rain clouds may flow into the plains, so it's a good idea to carry a folding umbrella when you go out, even if it's sunny.

Latest month forecast: The intense heat that continues through September: Western and Eastern Japan are again trending in rainy weather

2025/08/15 20:06

On Thursday, the Japan Meteorological Agency announced the latest one-month forecast, which will provide an estimate of the weather for the next month.



According to the prediction results from the numerical forecast model, the Pacific high pressure system is predicted to rise from the southeastern sea in Japan to the east and western Japan. North and Eastern Japan are subject to a period of mobility high pressure, while North, East and West Japan are likely to be covered by high pressure throughout the period.
On the other hand, since the Sea of Okhotsk side is a low-pressure area, it is expected to be affected periodically by low pressure and front lines, mainly on the Sea of Japan side of North Japan.
The average temperature around 1500m above the sky is high nationwide, and the area around Honshu is likely to be covered in warm air throughout the period.



In western and eastern Japan, high pressure will continue to be more likely to be covered in high pressure, so there will be more sunny days and the precipitation will be lower than normal. The weather in northern Japan is likely to change cyclically due to the effects of low pressure and fronts, but there will be many sunny days throughout the period, and precipitation will likely be on the same level as normal or less than normal.
From August 7th to 12th, due to the stagnant front and low pressure system, linear precipitation occurred in Kyushu and Hokuriku, causing record-breaking heavy rain. It looks like there will be a tendency for rain again in the future. Use water carefully on a daily basis.


The average temperature one month away will be higher than normal nationwide from Hokkaido to Okinawa. The Japan Meteorological Agency has released an "Early Weather Information on High Temperatures" stating that the average five-day temperature from around the 20th is likely to be significantly higher than normal. This information is intended to encourage caution at least six days in advance when the temperature is likely to rise that is only once every 10 years.



There is a possibility that there will be a record-breaking hot day in the future, and nighttime temperatures will continue to be less likely to drop. Be sure to take full precautions against heat stroke, day and night. You also need to be careful about managing your crops.

Tomorrow, severe thunderstorms and extremely severe thunderstorms in Tokai and Kanto - Warning: Weather changes suddenly in the future - The dangerous heat that exceeds the temperature will return

2025/08/15 13:11

Obon - the Pacific High Pressure Power will increase after the Obon holidays
Weekly Weekly Weekly Weekly Weekly Weather Forecast
#Warning for sudden weather Not only in the mountains, but also in the plains
#Dangerous heat that exceeds body temperature is expected to return to 38 C in Gifu, Nagoya, and Kofu
#Cannot be aware of sudden weather conditions as well as in the plains



#Warning for sudden weather Not only in the mountains, but also in the plains

The other day, due to the influence of the front, there was heavy rain around Honshu.
However, due to the growing influence of the Pacific High Pressure over the next week, the front line will be unclear near Honshu.
We expect sunny days to continue, mainly in western and eastern Japan.

However, tomorrow, the 16th (Saturday), clouds will likely spread on the Pacific Ocean side of the west and eastern Japan due to the influence of moist air.
In the Tokai and Kanto, due to the influence of valleys of atmospheric pressure, there are also areas where rain will fall in the plains.
There will be heavy rain and extremely heavy rain inland and along mountains.

From the next day, onwards, in western and eastern Japan, you should be careful of sudden changes in the weather even if it's sunny.
The air condition is likely to become unstable due to rising temperatures during the day or the effects of humid air.
In the afternoon, rain clouds tend to develop mainly inland areas and along mountains, so when leisure activities in the mountains, be careful of changes in the sky and keep safety first.
Also, rain clouds can flow into the plains, so it's safe to carry an umbrella that can be used in both sunny and sunny areas.



#Dangerous heat that exceeds body temperature is expected to return to 38 degrees Celsius in Gifu, Nagoya and Kofu
In the last few days, the heat has settled down for a while due to rain from the front.
However, the dangerous heat that exceeds the temperature has returned for the next week.
Again, there are more places where the highest temperature is over 35 C, and there will be some places where the temperature is dangerously high, not only in western Japan but also in eastern Japan, where the temperature is dangerously high, especially inland areas.
We expect the highest temperature to be in Gifu tomorrow, the 16th (Saturday), 37c in Kumagaya tomorrow, and 38c in Monday, the 18th (Mon) in Gifu, Nagoya, and Kofu.
In areas where a heatstroke warning alert has been issued, try to spend your time in a cooler environment with air conditioning indoors, taking frequent breaks, hydrate and salt.
This is a summer vacation, and it is a time when three generations of people go out more, but elderly people, infants, and young children are prone to heat stroke, so be careful and people around you should also talk to them.
Even in areas where heatstroke warning alerts have not been announced, when leisure activities outdoors, be sure to take thorough measures against heatstroke, such as drinking plenty of hydration, using hats and parasols, and taking breaks in cool places.





#Low pressure and fronts pass through the area around Northern Japan
Low pressure and fronts are expected to pass through one after another, and rain will likely fall in a short period, mainly on the Sea of Japan side.
Caution is required as there is a risk of heavy rain or thunderstorms locally.
On the days when the sun is exposed, the temperature will likely exceed 30 C in Hokkaido.

Heat stroke warning alerts are announced in Tokai and Western Japan

2025/08/15 06:34

The area around Japan is expected to continue to be covered by high pressure. The strong sunlight is shining, especially in western Japan, and the heat will continue today.

The forecast maximum temperatures are 30 C in Sapporo, 32 C in Sendai, 33 C in Tokyo, 36 C in Nagoya, 36 C in Osaka, 34 C in Kochi, and 35 C in Fukuoka.
In addition, in Hita, Kurume, and Saga, the temperature may exceed 38 C, which is expected to be 38 C. If you are working outdoors, such as those who are working in recovery from heavy rain, please take full precautions against heat stroke.



The Ministry of the Environment and the Japan Meteorological Agency have issued heatstroke warning alerts from Tokai to Western Japan, and have been announced for 22 regions.


In areas where a heatstroke warning alert has been issued, significantly higher temperatures can cause damage to human health due to heatstroke.
There are probably many people planning to go out during the Obon holidays, but in areas where the announcement is made, please refrain from activities during hot times as much as possible, and be careful to take frequent breaks, drink water and salt.
Also, use air conditioners indoors to ensure that you stay in a cool environment and take full advantage of heatstroke indoors.

Weather today, Friday the 15th: Rain mainly in the morning in northern Japan; Beware of sudden thunderstorms in eastern and western Japan

2025/08/15 06:12

Fronts and low pressure systems are expected to pass through northern Japan today, the 15th (Friday). Umbrellas are likely to be useful in northern Japan.
There are many places in Eastern and Western Japan covered by high pressure, and the heat will continue to be severe.



On the Sea of Japan side, rain will likely fall, mainly in the morning. Care must be taken in the Tohoku region as there is a risk of heavy rain or thunderstorms. The weather will improve in the afternoon, and there will be a place where the sun will return.


In many places in Kanto and western Japan, high pressure is covered in high pressure and the sunlight reaches you. There are some places, mainly in western Japan, where the temperature is extremely hot, above 35 C, so please take full precautions against heatstroke.
In the afternoon, there are likely to be a sudden thunderstorm, mainly along the mountains. When leisure activities in the mountains, be careful of changes in the sky.

[High sea surface temperatures continue] Sea of Japan and the seas around Hokkaido: up to 5-6 C higher than normal Ocean Summary 2025/8/3 - 8/9

2025/08/14 15:55

The sea surface temperatures continued to be higher than normal in the Japanese Sea and the waters surrounding Hokkaido, and were up to 5-6 C higher than normal.
Below is a summary of the oceans [August 3, 2025 - August 9]



#Pressure arrangement and waves
On the 3rd, Typhoon No. 9 moved eastward in Japan.
Also, at 9am, Typhoon No. 10 broke out east of Hachijojima, moving northeasterly east of Japan.
On the 4th, Typhoon No. 9 was transformed into a temperate cyclone far east of Japan at 3pm.
Typhoon No. 10 moved eastward in Japan.
The waves rose in the east of Japan, causing it to slam in the area around the typhoon.
From the 5th to the 6th, Typhoon No. 10 proceeded far east in Japan, turning into a temperate cyclone at 9am on the 6th.
Also, on the 8th, fronts passed around Honshu one after another, causing waves to rise slightly in the waters near Japan.
Typhoon No. 11 broke out in the Mariana Islands at 9am on the 8th.
Typhoon No. 11 headed north to the waters near Ogasawara on the 9th, causing a major storm around Typhoon No. 11.



#Sea surface temperature
The sea surface temperature in the Japanese Sea has been significantly higher than normal due to low pressure and passing fronts, and gradually it has become slightly higher than normal in the west and central parts.
In the East China Sea, the sea area remains at an average level.
On the Pacific side, the waters remained at normal levels, and in the east of Japan, where Typhoon No. 10 passed, the waters slightly lower than normal increased.
The off Sanriku area continued to be slightly higher than normal.
In the waters around Hokkaido, waters that were much higher than normal continued. In the Sea of Okhotsk, the temperature was up to 6 C higher than normal.

Obon - End of Obon - The dangerous heat that exceeds the temperature is revived - Warning of sudden changes in weather - Low pressure in the vicinity of northern Japan and front lines passing one after another

2025/08/14 12:06

Weekly weather forecast for Obon to end of Bon
#Dangerous heat that exceeds body temperature is revived; the Pacific high pressure system is becoming stronger
#Warning for sudden changes in weather, not only in the mountains, but also in the plains
#Low pressure and fronts pass through the northern part of Northern Japan one after another



#Dangerous heat that exceeds body temperature is coming back to power
Today, the 14th (Thursday), the Pacific high pressure system was strengthening, and the front that caused heavy rain on Japan the other day is moving north to the Korean Peninsula.
For the past few days, the heat around Japan has been calming due to the rain caused by the front line.
However, due to the growing influence of the Pacific High Pressure over the next week, it is expected to clear up, especially in western and eastern Japan.
And then the dangerous heat that exceeds the body temperature has returned.
Again, there are more places where the highest temperature is over 35 C, and there will be some places where the temperature is dangerously high, not only in western Japan but also in eastern Japan, where the temperature is dangerously high, especially inland areas.
In areas where a heatstroke warning alert has been issued, try to spend your time in a cooler environment with air conditioning indoors, taking frequent breaks, hydrate and salt.
This is a summer vacation, and it is a time when three generations of people go out more, but elderly people, infants, and young children are prone to heat stroke, so be careful and people around you should also talk to them.
Even in areas where heatstroke warning alerts have not been announced, when leisure activities outdoors, be sure to take thorough measures against heatstroke, such as drinking plenty of hydration, using hats and parasols, and taking breaks in cool places.



#Beware of sudden weather changes Not only in mountain leisure activities, but sunny days are expected in western and eastern Japan, but air condition is likely to become unstable due to rising daytime temperatures and the effects of humid air.
Please be careful of sudden changes in the weather.
In the afternoon, rain clouds will likely develop, mainly inland areas and along mountains.
When leisure activities on the mountain, be careful of changes in the sky and make safety your number one priority.
Also, rain clouds can flow into the plains, so it's safe to have an umbrella that can be used in both sunny and rainy areas.



#Low pressure and fronts are expected to pass through the area around northern Japan
Low pressure and fronts are expected to pass through the area around northern Japan.
In northern Japan, there will be more rainy days, mainly on the Sea of Japan side. Care must be taken as there is a risk of heavy rain or thunderstorms locally.
On the days when the sun is exposed, the temperature will exceed 30 C.

The heat is back. The next week is so hot

2025/08/13 17:16

A stagnant front extends from the East Sea of Japan through the South of Kanto, the Tokai region, and the Sea of Japan in the Yellow Sea.
In addition, there are cyclones on the east and Yellow Sea fronts of Japan, moving northeast.
On the other hand, there is a high pressure system in the northern Sea of Japan and the southern Sea of Japan, moving east and west respectively.

Today, the front line activities that caused heavy rain during the three-day holiday gradually weakened, and many areas were sunny, mainly in northern Japan and Kyushu.
The heat has returned to western Japan and the temperature has risen, and as of 4pm, there were 603 midsummer days across the country with a temperature of 30c and 24 extremely hot days of 35c or higher.




For the next week from tomorrow onwards, there will be many days when the high pressure will be covered in sunny and warm air, so
There are more and more places with hottest temperatures with a maximum of 35 degrees or higher up until mid-next week, the 20th (Wednesday), and the temperatures are expected to continue to be high in various places.




As a heat stroke prevention measure, it is important to stay hydrated frequently and avoid the heat.
It is important to avoid direct sunlight, especially when going out, by wearing a parasol or hat, and using the shade.
Also, don't worry about being indoors, and try to keep up with proper hydration and temperature control.



Specific measures to prevent heatstroke are as follows.

1. Avoid the heat:
When going out: Wear a parasol or hat and use the shade. Avoid going out during hot times.
Indoor: Make sure to control the temperature appropriately (use air conditioners and fans appropriately). Make sure to ventilate frequently.
When active: Don't overdo it on hot days and take frequent breaks.

2. Hydration:
Relax: Refreshing hydration frequently during the hot season to prevent dehydration.
Drinks suitable for hydration: Barley tea, oral rehydration solutions, sports drinks, etc. are suitable.

3. Salt supplement:
Salt supplement when sweating: It is also important to replenish the salt that is lost along with sweat.
Foods suitable for replenishing salt: Add a little salt to umeboshi, salted kelp, rice balls and other foods.

4. Clothing:
Breathable Clothing: Wear clothes made of breathable materials (cotton, linen, etc.).
Moisture-absorbing and quick-drying underwear: Choose underwear that is excellent in moisture-absorbing and quick-drying.

5. Health management:
Notes when you are not feeling well:
Special care is required when you are not feeling well, as the risk of heatstroke increases.
Note for the elderly:
Special care is required in elderly people as their temperature control function decreases.



In addition to health management such as heat stroke prevention, please be careful about managing agricultural products, livestock, etc.

Isesaki City, Gunma Prefecture, the highest highest temperature in history in Japan; special heavy rain warning in Kirishima City, Kagoshima Prefecture (August 3 - August 9, 2025)

2025/08/13 07:33

Here is a summary of the weather during this period (August 3rd to August 9th).

#Summary of weather for this period (August 3rd to August 9th)
The average temperature was covered by a tall, warm high pressure system, and in many places, especially in northern and eastern Japan, it exceeded normal. The temperature exceeded the average temperature in the Sea of Okhotsk side and the Pacific side of Hokkaido, and in Kanto, the temperature exceeded 3 C, and in Muroran, Maebashi and Tokyo, the temperature exceeded 3 C and in Kushiro.

Pressure exceeded normal years in northern Japan, Hokuriku, and Kyushu, which had heavy rain due to low pressure and fronts. In Kushiro, Akita, and Niigata, the number was about 4 to 5 times the average year, and in Kanazawa, where linear precipitation occurred, the number was about 12 times the average year. In Nagasaki, the total rainfall was about four times higher than normal, and in Kagoshima, the total rainfall was about twice higher than normal.

Sunday hours have increased cloudy and rainy days due to the effects of low pressure and fronts, and many areas have fallen below normal in the Sea of Japan side of Northern Japan, Hokuriku, and Western Japan. In the northern and eastern Japan Pacific side, there were many sunny days throughout the period, so many areas had more sunlight than usual.



[About the weather during this period]
#Characteristics of the atmospheric pressure arrangement
On the 3rd, high pressure was covered in the area around Honshu, and typhoon No. 10 occurred near the Izu Islands. The tropical cyclone of former Typhoon No. 8 traveled northeasterly through the East China Sea. On the 4th, Typhoon No. 10 left Japan's Tokai region. A low pressure system, derived from the warm, humid air of former Typhoon No. 8, is moving eastward from the Korean Peninsula. On the 5th, a low pressure system accompanied by a front passed through Hokkaido from the Sea of Japan. The front line stagnates near the Sea of Japan. Around Honshu, a pressure arrangement was formed at the southern and northern and low levels. On the 6th, the front line traveled east to west from Tohoku to Hanachu, and a low pressure system on the front line traveled eastward from the Korean Peninsula into the Sea of Japan. On the 7th, the low pressure system developed and progressed to the area near Hokkaido, and the front line from the center of the low pressure system stagnated from Tohoku to Hanachu. On the 8th, the front gradually moved south towards the southern coast of Honshu, and stagnated from the Chinese coast to the Kanto coastline, over Japan's Tokai. Typhoon No. 11 broke out near the Mariana Islands. On the 9th, the front line ran from Huachu through Kyushu and stagnated over Japan's Tokai region. In the south of Japan, Typhoon No. 11 moved westward.

#Precture
On the 3rd, the atmosphere became unstable due to rising temperatures during the day, and localized rain and thunderstorms along mountains and inland in the west and eastern Japan. Heavy rain of 44.0mm/h was observed in Shinshu Shinmachi, Nagano City. On the 4th, the rain began mainly in western Japan due to the effects of warm, humid air heading towards the low pressure system. Very heavy rain at 59.0mm/h was observed in Akune City, Kagoshima Prefecture. On the 5th, due to low pressure and the effects of fronts, there was record-breaking rain, mainly on the Sea of Okhotsk side of Hokkaido and the Sea of Japan side of Tohoku. The rains were extremely heavy, breaking the number one record in Kushiro City, Hokkaido (65.0mm/h) and Noshiro City, Akita Prefecture (65.0mm/h). On the 6th, heavy rain began to occur mainly in the Hokuriku region due to the influence of the front line. In Hashimo, Sado City, Niigata Prefecture, the highest recorded daily precipitation of 280mm. On the 7th, a linear precipitation zone occurred near the Kaga region of Ishikawa Prefecture at dawn. In Kanazawa, record heavy rainfall of 332.0mm is 24-hour rainfall. On the 8th, a special warning about heavy rain was issued in the early hours of the morning, with linear precipitation occurring near Kirishima City, Kagoshima Prefecture. On the 9th, heavy rain began mainly in northern Kyushu, near the front line, and a linear precipitation zone occurred around Fukuoka Prefecture late at night.

#Temperature
On the 3rd, warm air around 1500m above spread from western Japan to Tohoku, and it was extremely hot in various places. The number of hot spots is 319. On the 4th, strong sunlight and the warm air above caused a wide range of heat. In Komatsu City, Ishikawa Prefecture, the temperature reached 40.3 degrees Celsius, causing a dangerous heat. On the 5th, in the Kanto region, in addition to the warm air of about 1,500m above, the Fohn phenomenon caused by airflow across the mountain overlapped, causing high temperatures. In Isesaki City, Gunma Prefecture, the highest temperature in the nation was observed at 41.8 C. On the 6th, many hot spots continued to appear near Honshu, with Shizuoka City reaching 41.4 C, the second highest in history in the country. Central Tokyo (37.0c) marks the fifth consecutive day of extreme heat, while Yokohama (38.1c) marks the highest temperature ever recorded. On the 7th, due to the influence of the front, there were many cloudy and rainy areas, and the number of hot and hot spots decreased to 12 spots, 233 less than the previous day. On the 8th, temperatures rose, mainly in the inland areas of Tokai and Kanto. 36.9c is in Kiryu City, Gunma Prefecture. It's a hot day at 35.0 C in central Tokyo. On the 9th, the heat eased slightly due to the rain, and only two hot spots were in Nagoya (35.5c) and Tottori (35.2c).

El Nino Surveillance News: It is likely to be in peacetime in winter.

2025/08/12 20:00

The Japan Meteorological Agency announced the latest El Nino surveillance news on Tuesday, the 12th.


The sea surface temperature in the monitored sea area continues to be normal, and neither the El Nino nor La Nina phenomenon has occurred, so the situation continues to be normal.
In the future, there is a possibility that the state will temporarily become closer to the La Nina phenomenon around autumn, but this condition is predicted to not last long.


The difference from the standard sea surface temperature in the El Nino monitoring waters in July was -0.1 C, which was close to the standard. In addition, the five-month moving average used to determine the occurrence of El Nino and La Nina phenomena was +0.1 C in May, which was close to the standard value.
Sea surface temperatures in the Pacific equator region were higher than normal in the western part and lower than normal in the central part, while the eastern part was closer to normal.
The eastern winds (trade winds) in the lower atmosphere of the Pacific equator were stronger than normal in the central region, and were around average in the eastern region.
Convection activity became more active near Indonesia, but around the date line in the Pacific equatorial region, it was about the same as normal.
From the above process, the situation has become a peacetime state, not occurring either the El Nino or La Nina phenomenon.



According to forecasts from the Japan Meteorological Agency's Atmospheric Ocean Coupling Model, trade winds will continue to remain strong in the Pacific equator into the fall, and sea surface temperatures in the surveillance waters will fall. However, this condition does not last long, and we expect the sea surface temperature to rise over winter, approaching the standard value. Also, live commentary shows that cold water has not accumulated throughout the Pacific equator. Based on the above, it is possible that the condition may be close to the La Nina phenomenon around autumn, but this condition does not last long and is likely to continue in peacetime through winter (60%).


#What is the El Nino/La Nina phenomenon
The El Nino phenomenon is a phenomenon in which the sea surface temperature increases above normal from the Pacific equatorial region to the South American coast, and this condition continues for about a year.


On the other hand, the phenomenon in which the sea surface temperature continues to be lower than normal in the same sea area is called the La Nina phenomenon.


Once the El Nino or La Nina phenomenon occurs, it is thought that abnormal weather will occur around the world, including in Japan.