Record-wide "high temperatures" are even in the ocean; sea surface temperatures around Japan are "severely high" [Summary of the oceans, September 7th-13th, 2025]

2025/09/17 13:23

The average summer temperature in Japan this year (2025) was significantly higher than last year and the year before last, marking the highest for the third consecutive year.
It has also been an unusual summer, with records of extremely hot days and spots above 40 C.

Not only is the temperature at sea, but the sea surface temperature is quite high, and this year, the typhoon approaches the average year (three) but
The sea surface temperature has not dropped much.


Below is a summary of the oceans (September 7th to 13th, 2025).



#Pressure arrangement and waves
On the 7th, a cyclone with a front went eastward through Hokkaido, and a front extending from the
Cyclone made south through Honshu on the 8th.
On the evening of the 7th, the waves were 2m high off Noto.
On the morning of the 8th, the waves were around 3m off Sanriku, but the waves subsided overnight.

/From the 9th to the 11th, the front line stagnated near Honshu.
In the waters around Japan, the waves were around 1m high, and the waves remained relatively mild.

From the 12th to 13th, the pressure slope increased between the cyclone on the front that stagnates in the Sea of Japan and the high pressure that is increasing its strength near the Sea of Okhotsk. On the night of the 13th, the waves rose to around 3m from Sanin to Akita.





#Sea surface temperature
The sea surface temperature in the Japanese Sea is much higher than normal, and
On the central and western continental sides, it has been up to 5 C higher than normal.


In the East China Sea, higher than normal waters have spread.
The Nansei Islands also have a higher sea area than usual.

On the Pacific side, the average sea area has been reduced, and the average sea area has expanded to above normal.


The waters off Sanriku continued to be much higher than normal.
In the south of the coast of Kuril Island, lower than normal waters continue.

The Sea of Okhotsk has reduced the average sea area, and the
Coastal areas continue to be much higher than normal.

[Double typhoons to occur] Will "Typhoons No. 17 and No. 18" occur one after the next by tomorrow morning (information on tropical cyclones)

2025/09/17 11:56

As of 9am today, Wednesday, September 17th, two tropical cyclones (typhoon eggs) have emerged on the sea south of Japan.



The Tropical Cyclone A landed on Luzon, the Philippines while still in a tropical cyclone, and
The Tropical Cyclone B travels westward east of the Philippines.



It is expected that both tropical cyclones A and B will develop by tomorrow, the 18th (Thursday), and a double typhoon is expected.


If a typhoon occurs, it will be "Typhoon No. 17" or "Typhoon No. 18."



Information on tropical cyclone a
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ kt)
Maximum instantaneous wind speed 23 m/s (45 kt)
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

The typhoon that changes from tropical cyclone A has not developed much, and is expected to return to tropical cyclone in South China by the morning of Saturday the 20th.



Information on tropical cyclone b
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ kt)
Maximum instantaneous wind speed: 23 m/s (45 kt)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------


They will head north to the south of Okinawa towards the end of the week, with a storm zone expected to occur.

The forecast circle is still large, and the path and speed of the typhoon is not clear, but there is a "storm warning zone" in which a storm zone may enter the Sakishima Islands in Okinawa, so you need to be very careful about the trends in the typhoons ahead.



The future course of the typhoon and the speed of moving north will affect the balance and activity with the autumn rain front near Honshu.


Weather around Honshu may change dramatically over the next week, so
Please be sure to keep up to date with the latest information.

Tohoku Region 17th: Highly wary of landslides and lowland flooding

2025/09/17 07:40

A low pressure system accompanied by a front is moving east-northeast around the Primco State. The low pressure system that occurs on the front extending from this low pressure system will move northeasterly through the Sea of Okhotsk on the 17th, with a cold front passing through the Hokkaido region.



Another front extends from China to the Tohoku region through the Korean Peninsula and the Sea of Japan. This front line is expected to travel south from the Tohoku region on the 17th through the Sea of Japan, and south from eastern Japan on the 18th.
In Northern Japan to Western Japan, the air condition will be extremely unstable due to the effects of low pressure and warm, humid air flowing towards the front, as well as cold air above and rising daytime temperatures.

#Rain forecast

The 24-hour precipitation expected from 6:00 on the 17th to 6:00 on the 18th is high,
Tohoku region: 100 mm

/B: The 24-hour precipitation expected from 6:00 on the 18th to 6:00 on the 19th is high,
/B: The 24-hour precipitation expected from 6:00 on the 18th to 6:00 on the 19th is high,
: Tohoku region: 60 mm
/B: The 100 mm
/B: In the Tohoku region: 17th, be careful of landslides, low-cost flooding, river flooding and flooding. Also, be careful of severe gusts of winds such as lightning strikes and tornadoes in northern and western Japan from the 18th.

Typhoon No. 17 to occur; typhoon eggs east of the Philippines; after typhoon development, almost stagnates in the South China Sea [Tropical cyclone information]

2025/09/16 16:59

As of 3:00 p.m. today, the 16th (Tuesday), the Japan Meteorological Agency has announced that it is expected to develop into a typhoon within 24 hours regarding the tropical cyclone developing in the east of the Philippines.
As expected, if it develops into a typhoon, it will be called "Typhoon No. 17."



#Tropical Cyclone Tuesday, September 16th at 3pm
Existence Area East
Location of the Philippines east
Central location 15 20 minutes N latitude 123 40 minutes east
Move north-northwest Slow
Central pressure 1006 hPa
Maximum wind speed 15 m/s (near the center)
Maximum instantaneous wind speed 23 m/s
In the future, the tropical cyclone east of the Philippines will proceed northward, and will develop into a typhoon in the east of the Philippines at 3pm tomorrow, the 17th (Wednesday), and typhoons will develop in the east of the Philippines.
They will proceed westward on the 18th on the 18th, and reach the South China Sea by Friday the 19th, and are expected to develop even further.
Then, on Sunday the 21st, the movement will be slower and almost stagnant in the South China Sea.


We do not expect a direct impact on Japan.
For now, we do not expect to land in mainland China, but as the South China Sea will slow down for a few days, the impact may last for a long time in South China and elsewhere.
If you are planning to travel to this area, please be careful of the latest information.

Autumn rain front again to Japan tomorrow and tomorrow, the Tohoku Sea of Japan side, and the fear of heavy rain on the southern Kanto region, including Tokyo,

2025/09/16 12:05

#Autumn rain front returns to Japan again tomorrow, heavy rain will rain on the Sea of Japan side of the Tohoku region
Today, the 16th (Tuesday), the area around Japan is covered with high pressure, and the sun is reaching a wide range of air conditioning.
However, the autumn rain front is stagnating in mainland China, and will likely reach the central Japan Sea tonight, and tomorrow, the 17th (Wednesday) to the northeast.
The next day, the 18th (Thursday), is expected to head south from west to eastern Japan.



In Tohoku, the atmosphere will be extremely unstable due to the effects of warm, humid air heading towards the front line from the morning of the 17th (Wednesday) to the 18th (Thursday).
In particular, on the Tohoku Sea of Japan side, there are areas where heavy rain falls, like a 40mm bucket flipped over an hour due to lightning.
The 24-hour precipitation until the morning of the 18th (Thursday) is expected to be 100mm at a high location, and if the rain clouds develop more than expected or stagnate in the same location, there is a risk of heavy rain at the warning level.
Also, heavy rain of 30mm per hour will fall on the Tohoku Pacific side.
We expect the 24-hour precipitation to be 50mm until the morning of the 18th (Thursday).



On the Tohoku Sea of Japan side, beware and beware of landslides caused by heavy rain, flooding of low landslides, and rising rivers from tomorrow morning, Wednesday the 17th to the 18th (Thursday).
In addition, in Tohoku, be careful of damage to agricultural crops and agricultural facilities caused by severe gusts of winds such as tornadoes and lightning strikes, hail, from dawn to late at night, tomorrow, the 17th (Wednesday) to the end of the night.

#Autumn rain front: It will go down south of the west to south of the east Japan; heavy rainfall in Kanto; warning level in Kanto
Tomorrow, the 18th (Thursday), the autumn rain front is expected to go south of the west to south of the east Japan.
Also, the front line will become more active as the pressure valleys above pass through.
There are some areas where rain will be temporarily falling along the Sea of Japan side of the Western Japan, eastern Japan, and Tohoku.
Thunderclouds will also develop locally in the southern Kanto region, such as in Tokyo, and there is a risk of heavy rain at the level of warning.
Please be careful of the latest information.

Weekly weather forecast: Cloudy and rain due to the autumn rain front - the severe heat finally settles

2025/09/16 07:27

Over the next half of the week, it is likely that there will be more cloudy and rainy weather due to low pressure and front lines. However, the extreme heat will calm down.



The autumn rain front will be stagnant around Honshu tomorrow, the 17th (Wednesday). Warm and humid air will flow towards the front, and the rain will expand from Thursday the 18th, mainly in the region on the Sea of Japan side of northern Japan and western Japan. There are areas where heavy rain is locally accompanied by lightning, and there is a risk of heavy rain on the Sea of Japan side of the Tohoku region. Be careful of landslides, road flooding, and river flooding.



From the 19th to 20th, the area around Honshu is likely to be affected by low pressure and autumn rain fronts, and there will be many cloudy and rainy areas. However, as the front moves south, there will likely be many places where the heat will subside.
In Hokkaido and northern Tohoku, the autumn atmosphere will be enveloped in advance, and autumn leaves will gradually progress on high mountains.
In the Kanto region, due to the effects of cool winds from the northeast flowing, many places will not reach the expected maximum temperature of 30 C. However, the clouds are expected to continue and there are many days when it doesn't feel refreshed.
In western Japan, the expected maximum temperature is likely to be around 30 C, but it is unlikely that it will be extremely hot, such as a hot day ahead.


The harsh heat is finally upon us, and we are beginning to see an end. However, this is also the change of seasons, so please be careful when taking care of your health.

Today, the 16th (Tuesday) After the holidays, the area will be sunny. Be careful of sudden changes in weather in the afternoon, even in places where there is no umbrella mark.

2025/09/16 06:19

Today, the 16th (Tuesday), the end of the three-day holiday, will be covered in large high pressure areas around Honshu, with many areas likely to be sunny.
However, there are a lot of clouds in the Kanto region, and there is a possibility of rain in the morning. It would be a good idea to have an umbrella when you go out. It's sunny in the afternoon and the sun is likely to arrive.


The air in Hokkaido is likely to be dry and dry. There is a warm air around Honshu, so severe heat will continue throughout the area. Many of the expected maximum temperatures are above 30 C, and there are likely some places where the temperature is extremely hot in the area west of Tokai, with 37 C in Nagoya and 36 C in Osaka. Be careful of heat stroke.



In the afternoon, the air condition becomes unstable due to rising daytime temperatures and the effects of humid air. Rain clouds and thunder clouds are likely to develop mainly along mountains and inland, and rain clouds can suddenly develop in urban areas, causing guerrilla thunderstorms. Even if the weather forecast does not have an umbrella mark, the weather may change dramatically in the afternoon, so it is a good idea to go out with a folding umbrella just in case.

Even though the heat is severe, the footsteps of autumn gradually approach from around the weekend.

2025/09/15 17:59

A high pressure system is heading eastward off Sanriku.
In addition, there is a high pressure system in the southern seas of Japan, and it is almost stagnant.
On the other hand, the front extends from Japan's East Sea to East and West Japan, and from the Yellow Sea.

Today, the days were severely lingering from Tokai to Kyushu, when the sun was shining, and many of the areas were extremely hot, with the highest temperature exceeding 35 C.






[As of 5pm]
All over Japan, there are 515 midsummer days above 30c, and
31 hot days above 35c.

The top 10 highest temperature rankings are
1 Mie Prefecture Kuwana City Kuwana 36.9 c
2 Oita Prefecture Bungo-Ono City Inukai 36.2 c
2 Aichi Prefecture Toyota City Toyota 36.2 c
4 Kochi Prefecture Shimanto City Egawasaki 36.1 c
4 Shizuoka Prefecture Tenryu Ward, Hamamatsu City Tenryu 36.1 c
6 Tokushima Prefecture Mima City Anabuki 35.9 c
7 Kagoshima Prefecture Kanetsugu-cho, Hinata County, Kagoshima Prefecture Hinata Maeda 35.8 c
7 Gifu Prefecture Mino City Mino 35.8 c
7 Aichi Prefecture Shinshiro City Shinshiro 35.8 c
10 Shizuoka Prefecture Hamamatsu Chuo Ward Hamamatsu 35.7 c

Starting tomorrow, the 16th (Tuesday), after the holidays, the 16th, the summer air is covered in western Japan, and the heat will be severe.
This severe heat is likely to last until around the middle of the week, so please be careful not to let your guard down and take care of your health, such as heat stroke.




However, from the second half of the week to the end of the week, the autumn rain front went south and the weather fell, and after that, temperatures have been on a downward trend in western Japan as well, and
It seems that autumn air will start to enter the Kanto, Koshinetsu for the time being.

However, it is still around normal, and the monthly forecast predicts that temperatures will be higher than normal even through October, but
It seems that the harsh heat will gradually fade away.

Summer is still in mid-September: Extremely hot days forecast in Nagoya and Osaka; heatstroke warning alert announced in 13 regions

2025/09/15 06:57

Today, the 15th, many areas will exceed 30 C from eastern to western Japan, and the temperature will be covered in warm air, mainly on the Pacific side, so it will likely be a severe heat. The estimated maximum temperatures are 31 C in Tokyo, 36 C in Nagoya, 35 C in Osaka, 32 C in Kanazawa, 34 C in Kochi, and 33 C in Fukuoka. It's mid-September, but you should continue to be careful of heat stroke.


Northern Japan will also be covered by high pressure, and temperatures will likely rise in various places than the previous day. The estimated maximum temperatures are 28c, Obihiro 29c, and Akita 29c in Sapporo. It gets cold in the mornings and evenings, especially inland areas, so be careful of the temperature difference between the day.



The Ministry of the Environment and the Japan Meteorological Agency have issued heatstroke warning alerts from Tokai to Okinawa, and have been announced for 13 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 who plan to go out on their days off, but please continue to 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 prevention indoors.

Weather today, Monday the 15th: Sunny in Northern Japan; Beware of changes in the sky from East to Western Japan

2025/09/15 06:32

Today, the last day of the three-day holiday, the 15th (Monday), the front that heads south through Honshu will become unclear, and the Pacific side of northern Japan and western Japan will be covered by high pressure and the sunlight will be reached. It looks like the sky will be dominated by clouds in the Kanto region.



There are many sunny spots in northern Japan, making it seem like a calm and cheerful atmosphere. The temperatures rise during the day, but it gets cold in the mornings and evenings, so be careful of the temperature difference between the day. Also, it will rain in the Soya region in the afternoon, so if you are going out, please bring rain gear.


Although the sunlight occasionally reaches the Sea of Japan side of Kanto, Hokuriku, and western Japan, the sky is easily spreading with clouds. There is a lot of sunlight on the Pacific side from Tokai to Kyushu, and temperatures are likely to rise. Be careful of heat stroke.
Also, in the afternoon, there are some areas that cause sudden thunderstorms, mainly along the mountains from eastern to western Japan, so be careful of changes in the sky.