Tomorrow, the 21st (Tuesday), there is a risk of disaster-level heat in the Tokai and Kanto regions; 40 degrees Celsius expected in Kumagaya. Will this be the first extremely hot day of the year

2026/07/20 18:39

Tomorrow, the 21st (Tuesday) after the holidays, the Pacific anticyclone will become even stronger, so the intense heat is likely to continue mainly in the Tokai and Kanto regions.



In particular, Kumagaya City, Saitama Prefecture, is expected to experience intense heat of 40 degrees Celsius. This will be the first time this year that we have had such a hot day nationwide. Temperatures in Nagoya and Gifu are also expected to reach 39 degrees Celsius, which is just one step away from an extremely hot day.



The severe heat continues in Western Japan, with temperatures in places like Kyoto and Okayama likely to reach 37 degrees Celsius, exceeding body temperature.



A [Heatstroke Warning Alert] has been issued widely for tomorrow, mainly in Kyushu and southern Tohoku.
Please be extremely careful about heatstroke day and night, drink plenty of water and salt, and use air conditioning even at night to prevent heatstroke.




The Ministry of the Environment's "Heatstroke Prevention Information Site" updates information on the risk of heatstroke (Heatstroke Warning Alert) on a daily basis.
Please check the alert level in your area and act accordingly.

Also, the heat level has risen a notch this week, and the disaster-level heat is expected to continue from tomorrow onwards. Avoid going out in strong sunlight as much as possible and try to stay in a cool place.

A series of extremely hot days: Central Tokyo records its first extremely hot day of the year

2026/07/20 16:58

Today, the 20th (Monday), many areas around Honshu were covered in high pressure and were sunny, with strong sunlight shining down and making it extremely hot.



In the inland areas of eastern and western Japan, there are many places where the heat is dangerously high, exceeding body temperature. As of 3:20 p.m., the daily maximum temperature was 39.4c in Katsunuma, Koshu City, Yamanashi Prefecture, 38.6c in Toyota City, Aichi Prefecture, and 38.5c in Hatoyama, Saitama Prefecture. It was extremely hot, with temperatures exceeding 38 degrees Celsius in the top 10 locations with the highest daily temperatures.
As of 3 p.m. today, the 20th, the number of locations that have recorded extremely hot days of 35 C or higher is 243. In central Tokyo, AMeDAS observations have observed temperatures of 35 C or higher, marking the first extremely hot day of the year. As of 3:10 pm on the 20th, the highest temperature in Tokyo has reached 36.1c.



Tomorrow, the 21st (Tuesday), will have a similar atmospheric pressure distribution as today, the 20th (Monday). It is likely that there will be some rain on the Sea of Japan side of northern Japan, where the front is stationary, but areas from the southern Tohoku region to Kyushu and the Nansei Islands will be covered by a midsummer high-pressure system, and the maximum daytime temperature will likely rise to around 35c in many places. Inland, there are likely to be places where the heat is dangerously close to body temperature. Kumagaya City in Saitama Prefecture and Nagoya are expected to experience 39 degrees Celsius, while Maebashi, Kofu, Gifu and other areas are expected to experience 38 degrees Celsius.

Please continue to be extremely careful about heat stroke, drink plenty of water and salt, and take adequate breaks.

The end of the rainy season has been announced in the Tokai and Kanto regions. The severe heat will continue day after day, and there is a warning for heat stroke.

2026/07/20 12:21

On Monday, the 20th, Marine Day, the Japan Meteorological Agency announced that the rainy season appears to have ended in the Tokai and Kanto-Koshin regions.



The rainy season ended one day later than normal in the Kanto-Koshin region, and 22 days later than last year. In the Tokai region, the end of the rainy season was announced one day later than normal and 23 days later than last year.

*The rainy season is a seasonal phenomenon, and there is an average "transition" period of about 5 days between the start and end of the rainy season. In addition, the announcement of the start and end of the rainy season is preliminary information, and will be reconsidered in consideration of weather changes from spring to summer, and may be revised at a later date.



From now on, the area around Honshu will be covered in high pressure for many days, and the severe heat is expected to continue day after day, especially in eastern and western Japan. The temperature will not drop much at night, and the night will continue to be tropical.
From tomorrow, the 21st (Tuesday) after the holidays, the predicted maximum temperature in Tokyo will be 35 degrees Celsius or higher every day, and in Nagoya, the 22nd (Wednesday) and 23rd (Thursday) may be extremely hot days of 40 degrees Celsius.

Please be extremely careful about heatstroke day and night, drink plenty of water and salt, and use air conditioning even at night to prevent heatstroke.

Beware of sudden changes in weather in eastern and western Japan today, the 20th (Monday/Marine Day). There is a risk of thunderstorms mainly along the mountains in the afternoon.

2026/07/20 07:40

Today, the 20th (Monday/Marine Day), many parts of eastern and western Japan are expected to be covered in high pressure and be mostly sunny, but in the afternoon, people should be careful of sudden thunderstorms especially along the mountains.
When going out, please bring rain gear and pay attention to changes in the sky, especially if you are planning to take part in outdoor leisure activities.



Looking at the weather forecast at 6:00 pm today, it is predicted that it will be mostly sunny in eastern and western Japan, but that it will rain in places, mainly along the mountains.



Looking at the probability of a lightning strike at 6pm today, the probability of a lightning strike is high mainly along the mountains of eastern and western Japan.

Due to the rise in daytime temperatures and the influence of warm, humid air flowing in from the south, the atmospheric conditions will become unstable in the afternoon, leading to localized heavy rain with thunderstorms.
Please be careful of flooding of low-lying land, rising river water, and landslides. Also, be careful of gusts of wind such as lightning and tornadoes.
Please be aware of changes in the sky, and if there are signs of a developing cumulonimbus cloud approaching, please take precautions such as moving inside a building.

Weather for tomorrow 20th (Monday): Extreme heat continues from Okinawa to southern Tohoku

2026/07/20 05:21

The front is expected to stay near northern Tohoku, and a low pressure system is expected to pass over Hokkaido. Eastern and western Japan will be within an area of high pressure.



Many areas from Okinawa to the southern part of Tohoku are exposed to sunlight, so it is likely to be extremely hot. It will be hot and humid from the morning, with temperatures rising to around 35c during the day, and the temperature is not expected to drop much at night. As the southerly winds weaken, temperatures will tend to rise on the Pacific coast and inland. Take all possible precautions to prevent heat stroke, use a hat and parasol when going out, take frequent breaks, and drink water. The atmospheric conditions will become unstable in the afternoon, especially along the mountains, so please be careful of sudden strong rain and thunder.
Clouds are likely to spread in northern Tohoku and Hokkaido, and there will be occasional rain in some places. Please bring a folding umbrella when going out. Even if there is little sunlight, the humidity is high and it can feel hot and humid.



It is well known that tomorrow is Marine Day, but it is also the day of the moon landing. The anniversary is commemorated in honor of Apollo 11's successful landing on the moon. The moon will be visible late at night over a wide area of western and eastern Japan. Please take this opportunity to look up at the sky.

Weather for the week: Rainy skies in the Tohoku region. Be careful of dangerous heat and sudden rain in eastern and western Japan.

2026/07/20 04:13

The weather for the next week is expected to continue to be cloudy and rainy in the Tohoku region due to the influence of the seasonal rain front, while eastern and western Japan are expected to have many sunny days.
However, even if the weather is sunny, there is a possibility of rain showers mainly along the mountains due to rising daytime temperatures and warm, humid air flowing in from the south. Please be careful of sudden changes in the weather.



This week, the rainy season front is expected to stay near the northern part of Tohoku. There will be many rainy days, especially in the northern Tohoku region.
During the weekend from the 25th (Saturday) to the 26th (Sunday), a frontal low pressure system is expected to move eastward near Tohoku, so rain will spread over the Tohoku and Hokuriku regions.

Hokkaido has many cloudy and sunny days.
Eastern and western Japan will have many sunny days covered by high pressure from the south.
However, local atmospheric conditions may become unstable due to rising daytime temperatures and warm, humid air flowing in from the south. Even if it is sunny, there is a possibility of thunderstorms in the afternoon, mainly along the mountains. Please be careful of sudden changes in the weather.

If you notice that pitch black clouds are approaching, you hear thunder, or suddenly a cold wind is blowing, move into a sturdy building.
Heavy rain brought by well-developed cumulonimbus clouds can fall heavily over a small area in a short period of time. Be careful of lightning strikes, gusts of wind such as tornadoes, rising river waters, and flooding of low-lying areas.




Over the next week, temperatures are expected to be higher than normal in many places in northern and western Japan. It is predicted that a wide area of Kanto-Koshin, Tokai, and western Japan, including Tokyo, will experience extremely hot days with temperatures exceeding 35 degrees Celsius every day, while Nagoya is expected to experience extreme heat of 40 degrees Celsius from the 22nd to the 23rd.

Please take steps to prevent heat stroke, such as hydrating frequently, adding an appropriate amount of salt, and using a parasol or hat when outdoors. Since there are many places where the temperature is over 25 degrees Celsius in the tropics, make sure to use the air conditioner properly indoors even at night and don't overdo it.
Also, please check the heatstroke warnings issued jointly by the Japan Meteorological Agency and the Ministry of the Environment, and consider refraining from outdoor activities on the days when they are issued in your area.

There is a risk of sudden changes in the weather today. Be careful of thunderstorms when enjoying outdoor leisure activities.

2026/07/19 08:19

A low pressure system accompanied by a front is moving northeast west of Hokkaido, and warm, humid air is flowing toward this low pressure system.



Heavy rain has been observed in Hokkaido and Aomori prefectures near the low pressure system.
Currently, a level 4 landslide warning has been issued for Mutsu City and Sotogahama Town in Aomori Prefecture. Everyone should evacuate from dangerous cliffs and slopes.

Eastern and western Japan will have periods of sunshine, and daytime temperatures are expected to be higher than normal.
As a result of these effects, the atmospheric conditions in eastern and western Japan, which are south of the front, will become extremely unstable, and there is a risk that localized rain clouds will develop and cause heavy rain accompanied by thunder.



Eastern and western Japan are covered in humid summer air, so if active rain clouds stay in the same area, there is a possibility of warning-level heavy rain.
The ground has become loose in some places due to previous rains, so please be careful of landslides, flooding of low-lying areas, and sudden rises in rivers.

Many people are probably planning to spend the three-day weekend outdoors, such as in the mountains or at the river.



If there are signs such as sudden darkness in the area or cold wind blowing, it is a sign that cumulonimbus clouds are approaching. Please evacuate to a safe building.

There is a risk of sudden changes in the weather today. Be careful of thunderstorms when enjoying outdoor leisure activities.

2026/07/19 08:19

A low pressure system accompanied by a front is moving northeast west of Hokkaido, and warm, humid air is flowing toward this low pressure system.



Heavy rain has been observed in Hokkaido and Aomori prefectures near the low pressure system.
Currently, a level 4 landslide warning has been issued for Mutsu City and Sotogahama Town in Aomori Prefecture. Everyone should evacuate from dangerous cliffs and slopes.

Eastern and western Japan will have periods of sunshine, and daytime temperatures are expected to be higher than normal.
As a result of these effects, the atmospheric conditions in eastern and western Japan, which are south of the front, will become extremely unstable, and there is a risk that localized rain clouds will develop and cause heavy rain accompanied by thunder.



Eastern and western Japan are covered in humid summer air, so if active rain clouds stay in the same area, there is a possibility of warning-level heavy rain.
The ground has become loose in some places due to previous rains, so please be careful of landslides, flooding of low-lying areas, and sudden rises in rivers.

Many people are probably planning to spend the three-day weekend outdoors, such as in the mountains or at the river.



If there are signs such as sudden darkness in the area or cold wind blowing, it is a sign that cumulonimbus clouds are approaching. Please evacuate to a safe building.

Severe heat continues nationwide; high temperature warning issued in eastern and western Japan

2026/07/19 04:09

According to the general weather commentary provided by the Japan Meteorological Agency, there will be days when the area is covered by high pressure and warm air, so temperatures are expected to remain high across the country.
The temperature is expected to reach over 35 degrees Celsius in some places, so please take care of your health and avoid heat stroke.



# Period when you need to be careful about high temperatures
Eastern Japan: Around the 20th to 24th
Western Japan: Around the 24th

The Ministry of the Environment's "Heatstroke Prevention Information Site" updates information on the risk of heatstroke every day. Please check the alert level in your area and act accordingly.

[3-day weekend weather] Front and low pressure system approaching Hokkaido, 150mm of rain expected in one day, risk of warning-level heavy rain

2026/07/18 12:09

Over the three-day weekend, there is a risk of warning-level heavy rain in Hokkaido due to the influence of fronts and low pressure.
Today, the 18th (Saturday), a front is extending from the continent, through the Yellow Sea, the Korean Peninsula, and into the Sea of Japan, and the low pressure above the front is moving eastward through the Yellow Sea.
The front will extend near Hokkaido on the night of the 19th (Sunday) tomorrow, and a new low pressure system that has formed above the front will move toward the Oshima Peninsula.



Atmospheric conditions are expected to be unstable in Hokkaido as warm, humid air will flow in toward the low pressure system and front.
Heavy rain of up to 30mm per hour will fall locally on the Sea of Japan, Pacific Ocean, and Sea of Okhotsk sides during the three-day weekend from the night of today, the 18th (Saturday) to the 20th (Monday) the next day.
Heavy rain accompanied by intermittent thunderstorms is expected to occur, especially on the Sea of Japan and Pacific Ocean sides.



#Forecasted precipitation for 24 hours until the morning of tomorrow 19th (Sunday) [in areas with the most]
Northern Sea of Japan side 100mm
Southern Sea of Japan side 120mm
Western Pacific Ocean 150mm
Eastern Pacific Ocean 80mm

# Precipitation forecast for 24 hours from tomorrow until the morning of Monday 20th [in areas with the most]
Northern Sea of Japan 100mm
Southern Sea of Japan 100mm
Western Pacific 120mm
Eastern Pacific 100mm
Northern Sea of Okhotsk side 100mm



Please be careful of flooding of lowlands, rising river waters, and landslides due to heavy rain.
Depending on the degree of rain cloud development, there is a risk of heavy rain reaching warning level.
If you are planning a trip to Hokkaido for the 3-day weekend, please keep an eye on the latest information.