[Ocean Summary] Sea surface temperature in the Sea of Japan is 4c higher than normal in the east of Kanto from February 22 to 28, 2026

2026/03/05 11:28

Near Japan, there was a day when the gradient of atmospheric pressure became large around low pressure systems and fronts, and the sea turned into a barge in the Sea of Japan.
Also, to the east of the Kanto region, sea surface temperatures were significantly higher than normal, expanding to an area that was up to 4 C higher than normal.
Below is a summary of the ocean (February 22-28, 2026)



#Pressure distribution and waves
On the 22nd and 23rd, a low pressure system accompanied by a front moved northeast over Northeastern China and Primorye.
The waves were rising in the northern and central parts of the Sea of Japan, and the waves were gradually getting louder.
On the 23rd, wave heights reached 5m in western Hokkaido, and waves also increased in the south and east of Japan.
On the 24th, the atmospheric pressure gradient increased between the high pressure area near the Korean Peninsula and east of Japan and the low pressure system in Siberia, and high waves continued in the west of Hokkaido.
On the 25th, a front passed from the East China Sea to the southern coast of Honshu and extended to the east of Japan, and a low pressure system moved eastward along the eastern coast of Kyushu and east of Japan.
The waves rose in the waters around Kyushu.
From the 26th to the 28th, a low-pressure system off the coast of Kanto moved northeast to the east of Japan, and waves rose from the south of Japan to the east of Japan, and on the 26th it broke off the coast of Kanto, on the 27th from the east of Kanto to off the coast of Sanriku, and on the 28th off the coast of southeastern Hokkaido.



#Sea surface temperature
Sea surface temperatures in the Japanese waters expanded to areas where they were slightly higher than normal in the northern and western regions.
In the East China Sea, the sea area continued to be slightly higher than normal, while the sea area near the Nansei Islands continued to be near normal.
South of Japan is at normal levels, and off the coast of the Tokai region, areas slightly lower than normal have shrunk.
To the east of the Kanto region, sea areas with significantly higher than normal temperatures expanded, with temperatures up to 4 C higher than normal.
Offshore Sanriku continued to be slightly lower than normal.
The temperature off the southeast coast of Hokkaido was higher than normal, up to 3c higher.
Sea ice was stagnant in the waters near Chishima and the Sea of Okhotsk.

Weather for the week: The weather will be downhill from the west on the 6th (Friday); there is a risk of stormy weather in Hokkaido on the 8th.

2026/03/05 07:23

This weekend, a low pressure system will move through the Sea of Japan, and a front extending from the low pressure system will pass near Honshu. Please be careful of stormy weather in Hokkaido from around the 8th to 9th, with rain and thunderstorms increasing temporarily.



The next front or low pressure system is expected to approach from the west tomorrow, the 6th (Friday). In the Nansei Islands, please be aware of heavy rain with thunder in the Sakishima Islands from early morning until dawn. In western Japan, there will be places in northern Kyushu where it will start raining in the morning, and there will also be places in the Chugoku, Shikoku and Kinki regions where it will rain in the afternoon.
Warm, humid air will move towards fronts and low pressure systems, making it easier for rain clouds to develop, so there is a risk of localized thunderstorms and heavier rainfall. Please be careful of sudden rain that falls in a short period of time, and strong gusts of wind such as lightning and tornadoes.

The next day, on the 7th (Saturday), the low pressure system will develop and move northeast across the Sea of Japan, and the area of rain will shift to northern and eastern Japan.
In areas on the Pacific coast, even if it rains, it will be temporary and will not last long. Meanwhile, on the Sea of Japan side, cold air will move south due to the influence of a low pressure system, and there will be places in Tohoku and Hokuriku where the rain will turn to snow by the 8th (Sunday). It will continue to snow in Hokkaido, and around the 8th and 9th there is a risk of strong winds and rough weather, so please be careful.

After the front leaves Honshu, there will be many sunny days in western and eastern Japan, especially on the Pacific side, and daytime temperatures are expected to remain near normal in many places. From Kyushu to Tohoku, cedar pollen tends to fly on sunny days. Especially after the weather improves, the amount of hay fever may increase rapidly, so those who are sensitive to hay fever should take precautions against hay fever.

Tomorrow, the 5th (Thursday), snow and rain in northern Japan will mainly occur in the morning. Temperatures will rise from the Kanto region to the west. Be careful of the amount of cedar pollen scattered.

2026/03/04 21:18

Tomorrow, the 5th, the low pressure system moving over the sea east of Japan will continue to develop, and strong winds will continue from northern Japan to the Pacific side of eastern Japan.

Northern Japan will experience snow and rain mainly in the morning. Winds are strong, especially on the Pacific side, and people on the Pacific side of Hokkaido need to be careful of blowing air in the morning.



As the low pressure system gradually leaves the vicinity of Honshu, snow and rain in northern Japan are expected to gradually stop in the afternoon. However, on the Pacific side of northern and eastern Japan, rough conditions are expected to continue with swells. Please be careful of strong winds and high waves.

The area west of the Kanto region will be covered in high pressure and will have sunny skies in many places. Many places will be cold in the morning, but the sun will shine brightly during the day, and the temperature will rise significantly.

However, cedar pollen is easy to fly, and it is reaching its peak in many places. Please take precautions against hay fever by wearing masks and glasses when going out.

Be careful of heavy snow in Hokkaido, wind, snow and high waves in Tohoku, and strong winds and high waves in Kanto!

2026/03/04 17:31

To the east of the Boso Peninsula, there is a low pressure system with a front that is moving east-northeast.
There is also a low pressure system off the coast of Akita that is moving northeast.
The low pressure system east of the Boso Peninsula is rapidly developing and moving northeast, and will move off the coast of Sanriku tomorrow morning.



Currently, snow is falling widely in Hokkaido, and a heavy snow warning has been announced in the Tokachi region.
Also, it is snowing and raining in places in Tohoku, and raining and snowing from Hokuriku to the Chugoku region on the Sea of Japan side.



The area around Hokkaido will be in a pressure trough from the 4th to the 5th, including a low pressure system in the Sea of Japan and a low pressure system rapidly developing east of Japan and moving northeast.
In the Tokachi region, please be on guard for traffic disruptions due to heavy snow late into the evening of the 4th.

On the Pacific side of the Tohoku region, strong winds will blow from the north, accompanied by snow, and the sea will continue to be rough due to swells.
Depending on the degree of development and course of the low pressure system, there is a possibility of blizzard and warning level high waves from the north.
Please be careful of wind and snow through the evening of the 5th and high waves through the 6th.

In the Kanto region, strong winds will blow mainly on the sea towards the beginning of the night of the 5th, and there will be some places where there will be heavy swells into the 6th.
In the Kanto region, please be aware of strong winds mainly at sea through the early evening of the 5th, and high waves with swells through the 6th.



#Snow report
24-hour snowfall as of 15:00 on the 4th (preliminary report by AMeDAS)
Hokkaido Nakasatsunai Village Kamisatsunai 42 cm
Hokkaido Taiki 42 cm
Hokkaido Hiroo 41 cm

#Snow forecast
The 24-hour snowfall expected from 18:00 on the 4th to 18:00 on the 5th will be heavy in some places
Western Hokkaido Pacific side 40cm
Eastern Hokkaido Pacific side 40cm

#Wind forecast
Maximum wind speed (maximum instantaneous wind speed) expected from the 4th to the 5th
Tohoku Pacific side sea 18 meters (30 meters)
Tohoku Pacific side land 15 meters (30 meters)
Kanto region sea 18 meters (30 meters)
Kanto region land 17 meters (30 meters)

Maximum wind speed expected on the 5th (maximum instantaneous wind speed)
Kanto region sea 15 meters (25 meters)
Kanto region land 15 meters (30 meters)

#Wave forecast
Wave height expected from the 4th to 6th
Tohoku Pacific side 5m with swell
Kanto 5m with swell

Wave height expected on the 5th
Kanto 4m with swell

Wave height expected from the 6th
Kanto 4m With swells

#Disaster prevention matters
In Hokkaido, there are already heavy snowfalls on the Pacific side.
In southern Tokachi, please be on guard for traffic disruptions due to heavy snow late into the evening of the 4th.
On the Pacific side, please be careful of traffic disruptions due to heavy snow, avalanches, and snow deposits on power lines due to wet snow into the early hours of the 5th.
Depending on the trend of the low-pressure system, snow clouds may continue to flow into the same area, potentially expanding the area with warning-level heavy snow.

On the Pacific side of Tohoku, please be careful of traffic disruptions and damage to buildings due to strong winds from the north accompanied by snow into the evening of the 5th.
Also, please be aware of damage to ships and coastal facilities due to high waves through the 6th.

In the Kanto region, please be aware of strong winds mainly at sea from early on the evening of the 5th, and high waves with swells into the 6th.

Caution/warning for strong winds and localized heavy snow through tomorrow 5th (Thursday) [Weekly weather]

2026/03/04 14:34

From now until tomorrow the 5th (Thursday), we need to be careful about strong winds and locally increasing snowfall.



Now, let's take a look at the state of rain, snow and clouds around this time.
The active rain clouds associated with the low pressure system are gradually moving eastward. However, snow clouds and rain clouds are starting to form over Hokkaido due to another low pressure system.



This is the forecasted weather map for tonight.
A low pressure system is expected to rapidly develop off the coast of Sanriku.
Also, another low-pressure system is expected to approach Hokkaido, and the northern evening winds are likely to become stronger mainly in eastern and northern Japan near these two low-pressure systems.
There are likely to be warning-level storms in some places, and the snow is likely to increase locally.

Let's take a look at the snow and rain forecast.
After this, snow is expected to gradually fall over a wide area, mainly in eastern Hokkaido, from the evening onwards.
In areas such as the Tokachi region, there are local purple signs, indicating that there may be snow in some places.


The amount of snow expected by the morning of tomorrow 5th (Thursday) is expected to be up to 60 centimeters in Hokkaido and 40 centimeters in Tohoku.
In Tohoku, there will be heavy snow mainly along the mountains, and in Hokkaido, there will be heavy snow in localized areas, mainly in the Tokachi region.
Then, around noon on the 5th (Thursday),
the snow and rain are likely to stop in many places, but the strong winds are likely to continue into the 5th (Thursday).



, we will take a look at the detailed weather of each place.
Today, the 4th (Wednesday), there is a need to be wary of strong winds mainly in eastern and northern Japan. The Pacific side of western and eastern Japan will be sunny, but the Sea of Japan side is expected to experience cold rain and snow. In Hokkaido, the snow is accumulating locally, and there is a risk that the wet snow may land on power lines.
Please be careful of power outages.



Weekly forecast.
Tomorrow, the 5th (Thursday), the snow in Hokkaido is expected to clear up from last week, mainly on the Pacific side.
As the strong winds continue, cedar pollen is likely to be scattered quite a lot.
Please take precautions against hay fever.

On the 6th (Friday), the rain will spread from the west.
It is likely to rain and snow over a wide area on the 7th (Saturday).
It looks like it will be sunny in many places after the 8th (Sunday).
It will continue to snow in Hokkaido.

Heavy snow is likely on the Pacific side of northern Japan. Be careful of traffic disruptions due to heavy snow.

2026/03/04 07:00

A low pressure system is located near the Izu Islands and is moving east-northeast.
This low pressure system is expected to rapidly develop and move east of Japan into tomorrow, the 5th (Thursday).
For this reason, on the Pacific side of northern Japan, wet snow will fall intermittently, resulting in heavy snowfall in some places.
Also, strong winds are expected to blow from the north, accompanied by snow, mainly on the Pacific side of Tohoku, and the sea is expected to continue to be rough due to swells.
If the temperature is lower than expected, there is a possibility of heavy snowfall of warning level, and depending on the degree of development and course of the low pressure system, there is a possibility of blizzard from the north and high waves of warning level.




#Expected amount of snow (in areas with the most)
+24-hour snowfall expected by dawn on the 5th (Thursday) tomorrow
Western Hokkaido Pacific side 60cm
Eastern Hokkaido Pacific side 60cm
Tohoku Pacific side mountainside 40cm
Tohoku Pacific side, flat land 30cm

#Expected wind forecast
+Maximum wind speed (maximum instantaneous wind speed) expected through tomorrow 5th (Thursday)
Tohoku Pacific side, sea 18 meters (30 meters)
Tohoku Pacific side land 15 meters (30 meters)

# Expected wave height
+Expected wave height from today 4th to tomorrow 6th (Friday)
Tohoku Pacific side 5 meters with swells

# Prevention Disaster
In Hokkaido, the snow will become heavier in some places, mainly in the Tokachi region and eastern Hidaka, from noon today on the 4th until dawn on the 5th (Thursday), and in the northern part of Tohoku on the Pacific Ocean side, from the night of the 4th today to the morning of the 5th (Thursday), there will be heavy snowfall.
Be careful of traffic obstructions caused by heavy snow, falling snow from roofs, and damage to buildings and agricultural facilities, and be careful of wet snow accreting on power lines and trees, as well as avalanches. In addition, on the Pacific side of Tohoku, please be on guard against traffic disruptions and damage to buildings due to strong winds from the north, accompanied by snow, through the evening of the 5th (Thursday) tomorrow, and damage to ships and coastal facilities due to high waves through the 6th (Friday).

Be careful of snowfall in the Kanto region from today 3rd to tomorrow 4th, and be careful of heavy snow on the Pacific side of northern Japan.

2026/03/03 13:53

Today, the 3rd (Tuesday), is the Doll's Festival, and due to the influence of a low pressure system moving east-northeast along the southern coast of Honshu, rain and snow are falling over a wide area.
After this, there will be snow in many places from Kanto-Koshin to Hokkaido.
In the Kanto region, snow is expected to fall mainly along the mountains and in mountainous areas from the afternoon of today, the 3rd (Tuesday) until noon on the 4th (Wednesday) tomorrow. If the surface temperature is lower than expected, there is a possibility of snowfall in the 23 wards.
In addition, through tomorrow, the 4th (Wednesday), the rain and snow will spread to northern Japan, and there is a risk of heavy snow on the Pacific side of Tohoku and Hokkaido.



Currently, there is a low pressure system with a front off the coast of Shikoku, and it is moving east-northeast. It is raining and snowing widely in China, from Shikoku to the southern part of Tohoku.

After this, temperatures in the Kanto-Koshin region are expected to drop and snow will turn to snow in many places. From the afternoon of today, the 3rd (Tuesday) to the early afternoon of tomorrow, the 4th (Wednesday), heavy snow will fall mainly along the mountains and in the mountains, and there will be snowfall in some places in the flatlands of the southern Kanto region.

The total amount of snowfall for the two-day period from 6 a.m. on the 3rd to 6 a.m. on the 5th is expected to be 50 cm in the mountains of northern Kanto, 15 cm along the mountains in the south, 13 cm in the plains of the north, and 1 cm in the plains of Saitama and western Kanagawa prefectures.
Be careful of traffic obstructions caused by snow accumulation and frozen roads, and be careful of snow accumulation and avalanches.

The maximum temperature in Tokyo today, the 3rd (Tuesday), is expected to be 8c, 6c lower than yesterday. Please take proper measures against the cold.
Also, the wind is strong and it is likely to rain or snow, so please be careful when going out.



On the 4th (Wednesday), a low pressure system is expected to rapidly develop and move northeastward east of Japan.

On the Pacific side of Tohoku, there will be heavy snow in some places, even in flat areas, from late on the night of the 3rd (Tuesday) until the 5th (Thursday). In addition, strong winds will blow from the north, bringing snow and swells at sea. If temperatures are lower than expected, there is a possibility of heavy snowfall. Depending on the degree of development and course of the low pressure system, there is a possibility of strong winds blowing from the north or warning-level high waves.
The total snowfall for the two days from 6:00 am on the 3rd to 6:00 am on the 5th is expected to be 90 cm along the mountains on the Pacific coast of Tohoku, and 70 cm on the flatlands.

On the Pacific side of Hokkaido, the snow will become heavier from noon on the 4th (Wednesday) to the 5th (Thursday), and there will be heavy snowfall in some places, especially in the Tokachi region and eastern Hidaka. Depending on the trend of the low pressure system, snow clouds may continue to flow into the same area, leading to warning-level heavy snow.
The total amount of snowfall for the two days from 12:00 on the 3rd to 12:00 on the 5th is expected to be 90cm in the western Pacific side and 80cm in the eastern Pacific side.

Please be careful of traffic obstructions caused by heavy snow, avalanches and falling snow from roofs, and snow buildup on power lines due to wet snow.

Weekly weather: After the weather improves, be careful of cedar pollen scattering; weather is expected to deteriorate nationwide on the weekend

2026/03/02 13:09

From this weekend (Saturday) onwards, there is a possibility that the weather will deteriorate again across the country.



Tomorrow, the 3rd (Tuesday) and 4th (Wednesday), due to the influence of a low pressure system on the south coast, northern and eastern Japan will experience cold rain and snow, and there will be localized areas of heavy snow along the mountains and inland. There is a possibility of snow accumulating in some areas even on the plains, so please be careful of deteriorating road conditions. From the 3rd (Tuesday) to the 4th (Wednesday), northern and eastern Japan will experience a temporary return to cold weather, with daytime temperatures not rising much and making it feel colder. Meanwhile, the weather in western Japan is expected to improve on the 4th (Wednesday) and bring spring warmth.

On the 5th (Thursday), it will likely snow in some places in Hokkaido, but the weather is expected to improve from Tohoku to Kanto-Koshin and Hokuriku. However, after the weather improves, the amount of cedar pollen scattered tends to increase. There are some places where cedar pollen has already reached its peak, so those who are sensitive should take precautions.

Around Friday the 6th, a new front and low pressure system will approach from the west, and the weather is expected to deteriorate again from the west. The low pressure system will then continue to develop as it moves through the Sea of Japan, and is expected to pass through northern Japan around Monday the 9th of next week. On Saturday the 7th, it will rain across the country, and there will be some places in northern Japan where it will snow. Especially in Hokkaido, there is a possibility that the effects of the low pressure system will continue to bring snow and strong winds, resulting in rough weather, so please pay close attention to the latest weather information that will be updated in the future.

Weekly weather: After the weather improves, be careful of cedar pollen scattering; weather is expected to deteriorate nationwide on the weekend

2026/03/02 08:18

There is a possibility that the weather will deteriorate again across the country from the weekend (Saturday) onwards.



Tomorrow, on the 3rd and 4th, due to the influence of a low pressure system on the south coast, northern and eastern Japan will experience cold rain and snow, and there will be localized areas of heavy snow along the mountains and inland. There is a possibility of snow accumulating in some areas even on the plains, so please be careful of deteriorating road conditions. From the 3rd to the 4th, there will be a temporary return of cold weather from northern Japan to eastern Japan, and daytime temperatures will not rise much, making it feel colder. On the other hand, the weather in western Japan is expected to improve on the 4th and bring spring warmth.

On the 5th, it looks like there will be snow in some places in Hokkaido, but the weather is expected to improve from Tohoku to Kanto-Koshin and Hokuriku. However, after the weather improves, the amount of cedar pollen scattered tends to increase. There are some places where cedar pollen has already reached its peak, so those who are sensitive should take precautions.

Around Friday the 6th, a new front and low pressure system will approach from the west, and the weather is expected to deteriorate again from the west. The low pressure system will then continue to develop as it moves through the Sea of Japan, and is expected to pass through northern Japan around Monday the 9th of next week. On Saturday the 7th, it will rain across the country, and there will be some places in northern Japan where it will snow. Especially in Hokkaido, there is a possibility that the effects of the low pressure system will continue to bring snow and strong winds, resulting in rough weather, so please pay close attention to the latest weather information that will be updated in the future.

Today, the 2nd (Monday), the weather is going downhill from the west. Tomorrow, the 3rd (Tuesday), there will be cold rain and snow in northern and eastern Japan, with the possibility of snow in the plains.

2026/03/02 07:34

Today, the 2nd (Monday), a low pressure system and front are approaching from the East China Sea. Developed rain clouds associated with low pressure and fronts are approaching from the west, and it is already raining in some places in Kyushu and the Nansei Islands.



The low pressure system accompanied by the front is expected to move along the southern coast of Honshu, and the rain will gradually spread over western Japan. In southern Kyushu and Okinawa, please be careful of heavy rain accompanied by thunder from noon to evening. In Chugoku, Shikoku, and Kinki, the weather will gradually change to rain from the afternoon. It is likely that there will be places in the Tokai and Kanto regions where it will start raining late at night.



Tomorrow, the 3rd, the low pressure system will continue to move along the southern coast of Honshu. From early morning until noon on the Pacific side of western Japan, be careful of heavy rain accompanied by thunder in Shikoku and the Kii Peninsula. From Kanto-Koshin to the southern part of Tohoku, there will be freezing rain and snow, and there are likely to be some places along the mountains and inland where the snow will be heavier. Because the low-pressure system is moving eastward relatively slowly, cold rain and snow are expected to continue for a long period of time from northern to eastern Japan into the 4th (Wednesday).



In particular, in northern and eastern Japan, snowfall will be heavier in localized areas, especially inland and along mountains. The snow is expected to spread to the plains, and if the snow continues to fall, there is a risk that snow will accumulate even in the plains of the Kanto region. From the 3rd tomorrow to the 4th, please be careful of deteriorating road conditions and snow accumulation.