1-month forecast: Temperatures will rise nationwide. There will be fewer sunny days on the Pacific side of eastern and western Japan.

2026/04/18 11:58

On the 16th (Thursday), the Japan Meteorological Agency announced the forecast for the month from April 18th to May 17th.
Temperatures are expected to rise nationwide over the next month. In addition, eastern Japan and western Japan on the Pacific side are likely to be affected by fronts and humid air, and the weather will likely be unstable.



Prediction results from the numerical forecast model.
Monthly average sea level pressure (figure on the left) predicts a high pressure system east of Japan and a weak pressure trough from the East China Sea to the vicinity of Honshu. East Japan and the Pacific side of western Japan will be susceptible to the influence of moist air and fronts that revolve around the edges of high pressure systems. Okinawa/Amami will likely be covered by high pressure mainly during the first half of the period.

Temperatures at approximately 1,500 meters above sea level (figure on the right) will be higher than normal nationwide, and eastern and western Japan will likely be covered in warm air.




Forecast of average temperature, precipitation, and sunshine hours for the next month, and weekly average temperature (probability of occurrence (%)).
The whole country is likely to be covered in warm air, and temperatures will be high over the next month. Temperatures are expected to be quite high at the beginning of the period in northern Japan, Okinawa and Amami, and during the first half of the period in eastern and western Japan.

As they are susceptible to the effects of fronts and humid air, eastern Japan and western Japan's Pacific side will likely experience near-normal or above-average precipitation over the next month. Therefore, in the Pacific side of eastern and western Japan, sunshine hours are expected to be at or below normal over the next month.
Okinawa/Amami is likely to be covered by high pressure mainly during the first half of the season, so precipitation over the next month will be at or below normal and there will be many hours of sunshine.

With Golden Week coming up from the end of April to May, many people will be planning to go out. Temperatures are expected to be higher than normal, so please be sure to take precautions against heatstroke when enjoying outdoor leisure activities.
Also, there will be many days when the weather will be bad, especially in eastern Japan and the Pacific side of western Japan. It's a good idea to check the latest weather forecast and plan accordingly.

The weather for today, the 18th (Saturday): Northern Japan is prone to rain, western Japan is also not clear, and Kanto is a good day for going out.

2026/04/18 06:21

Today, the 18th (Saturday), a low pressure system will approach northern Japan, so there will be some places in northern Japan where it will rain. The weather in western Japan is also expected to be cloudy, with some areas expected to rain. There will be many sunny places in the Kanto and Tokai regions.



There will be a lot of clouds in northern Japan, and it will rain briefly during the day. Please pay close attention to changes in the sky as there is a risk of locally heavy rain and thunderstorms.
There is also a possibility of showers in Hokuriku around noon. It's safe to have a folding umbrella when going out.

The weather is not expected to deteriorate in the Kanto and Tokai regions, and it will be sunny and a good day to go out. Please be aware of the temperature difference between morning and evening and during the day.

Western Japan has a cloudy sky due to the humid air. Sunny skies will return to the Kinki region in the afternoon, but in Chugoku, Shikoku, and Kyushu, clouds tend to spread, and showers are possible, so it's best to bring rain gear such as a folding umbrella when going out.

There will be some places in Okinawa where it will rain, especially in the morning. It looks like there will be some places where the sun will return in the afternoon.

[Typhoon No. 4] Heading north near Ogasawara, high wave warning in Ogasawara Islands until late at night on the 18th tomorrow

2026/04/17 19:58

As of 6:00 p.m. today, the 17th, Typhoon No. 4 is located near Ogasawara and is moving northeast at a speed of approximately 15 kilometers per hour.
The Ogasawara Islands are experiencing severe swells due to the typhoon's swells and increasing pressure gradients, resulting in stronger winds, and a wave warning has been issued.

#Typhoon No.4 17th (Fri) 18:00
==================/br Size Large
Strength Strong
Center location Near Ogasawara
Movement Northeast 15km/h
Central pressure 965 hPa
Maximum wind speed 35 m/s (near the center)
Maximum instantaneous wind speed 50 m/s
==================



The typhoon is expected to gradually increase speed and move northeast. It will move toward the waters near Minamitorishima on the 19th (Sunday), and will turn into an extratropical cyclone on the 20th (Monday).
Although it is expected to pass relatively far from the Ogasawara Islands, there is a risk that it will be affected by high waves with swells into tomorrow, the 18th (Saturday).



Please be careful of high waves accompanied by swells in the Ogasawara Islands until late at night on Saturday the 18th. Also, please be careful of high waves accompanied by swells on the 19th (Sunday).

#Expected wave height (with swells)
+Expected wave height for today 17th
Ogasawara Islands 6m
+Expected wave height for tomorrow 18th (Saturday)
Ogasawara Islands 6m
+Tomorrow 19th Expected wave height on Sunday
Ogasawara Islands 5m

Typhoon No. 4 is expected to have little impact on areas around Japan, but swells will reach from eastern Japan to the Pacific side of western Japan, causing waves to rise, so caution should be taken when enjoying leisure at sea.

Name of day with maximum temperature of 40 degrees or higher decided

2026/04/17 13:05

The Japan Meteorological Agency announced today, April 17th (Friday), that days when the maximum temperature reaches 40 degrees Celsius or higher will be called ``severe heat days.''

The Japan Meteorological Agency conducted a
survey on the Japan Meteorological Agency website from February 27th to March 29th, 2020, and the
decision was made based on the survey results and opinions from experts.

``Hot summer day'' received the most support in the survey, and
experts also commented that it is socially familiar and appropriate for the Japanese language, so we decided on the name as it was judged to be the most appropriate name.

From this year onwards, 25 degrees or higher will be considered a "summer day," 30 degrees or higher will be considered a "midsummer day," 35 degrees or higher will be considered a "hot day," and 40 degrees or higher will be considered an "extremely hot day."

Last year, Japan's highest temperature of 41.8 degrees Celsius was recorded in Isesaki City, Gunma Prefecture on August 5th, showing a noticeable trend in high temperatures.
You need to be careful about heatstroke even if it's not a "severely hot day," but you need to be even more cautious on a "severely hot day."


#Questionnaire results
+Extremely hot day 202,954
+Extremely hot day 65,896
+Extremely hot day 25,638
+Scorching hot day 22,292
+Extremely hot day 21,930
+Extremely hot day 20,282
+Hot day 9,219
+Hot day 8,782
+Very hot day 4,595
+Hot day 4,396
+Hot day 3,341
+High heat day 1,478
+High heat day 865

Weather for the week: Summer days are expected in Tokyo and Nagoya on the 19th; watch out for high waves in the Ogasawara Islands due to the approaching typhoon

2026/04/16 12:11

Over the next week, high pressure is expected to bring many sunny days in many parts of the country, and temperatures are expected to rise in many parts of the country. Especially on the weekend, the 19th (Sunday), temperatures are expected to reach 26 degrees Celsius in Tokyo and Nagoya.
Typhoon No. 4 is expected to approach the Ogasawara Islands, and there is a possibility of warning-level high waves from tomorrow, the 17th (Friday). Also, please be careful as the wind is likely to increase.



The front and low pressure system that brought rain over a wide area yesterday, the 15th (Wednesday) are moving away to the east of Japan, and high pressure is expanding from the west.
Today, the 16th (Thursday), it was raining in the morning on the Pacific side of eastern and northern Japan, but the weather is improving. Sunshine will return over a wide area in the afternoon. However, from the Tohoku region to the Kanto region, there are likely to be showers accompanied by thunder in some places, so please be careful of changes in the sky. It's safe to have it foldable when you go out.



Tomorrow, the 17th (Friday), the area around Japan will be widely covered by high pressure, and it will be sunny in many places.

In addition, Typhoon No. 4, a large and very strong typhoon, is slowly moving north near the Mariana Islands. The typhoon is expected to gradually change its direction to the northeast and move from the Mariana Islands through the waters near Ogasawara to the waters near Minamitorishima. In the Ogasawara Islands, the swells from the typhoon have turned them into barges. Please be on guard for high waves with swells from early on the night of the 17th until the 18th. The wind is also expected to increase. Please check the latest information.



A low pressure system is expected to pass near Hokkaido on the 18th (Saturday). A low pressure system is also expected to remain near the East China Sea. Clouds will spread mainly over northern and western Japan, and it will rain in Kyushu and Shikoku.

On the 19th (Sunday), the area around Japan will be covered in high pressure, and it will be sunny in many places. There will be plenty of sunshine, and even in eastern Japan, temperatures are expected to reach 26c in Tokyo and Nagoya, making it a summer day.

A low-pressure system accompanied by a front is expected to move eastward near Sakhalin from the 20th (Monday) to the 21st (Tuesday). There will be rain in some places, mainly in northern Japan, due to the influence of a front extending from a low pressure system.

On Wednesday the 22nd, the area around Japan is expected to be covered in high pressure and sunny in many places.

On the 23rd (Thursday), a low pressure system accompanied by a front is expected to move eastward from near the Yellow Sea. The weather will be downhill from the west.




Temperatures are expected to be around normal or higher than normal in many places throughout the period. The maximum temperature is expected to be similar to that of May or June in some places. On the other hand, there are days when it can still be cold in the morning, so it's a good idea to choose clothes that can be adjusted.
Also, since this is a time when people are not used to the heat, please take frequent breaks and stay hydrated to prevent heat stroke. On sunny days, it's a good idea to bring a parasol or hat when you go out.

[Marine Summary] Wave height is 5m in the east of Kanto, sea surface temperature in the Sea of Japan is 5c higher than normal (April 5th to 11th, 2026)

2026/04/16 11:19

The pressure gradient between the low-pressure front and the high-pressure front increased, and wave heights reached a maximum of 5 meters in the eastern part of Japan and the eastern Kanto region.
Sea surface temperatures in the waters of Japan were significantly higher than normal, with temperatures up to 5 C higher than normal on the western continental side.
Below is a summary of the ocean (April 5-11, 2026)



#Pressure distribution and waves
On the 5th, a front extended from the sea near Okinawa to the east of Japan, and a low pressure system moved eastward through the Sea of Okhotsk.
The gradient of atmospheric pressure increased between Japan and the high pressure system east of Japan, and wave heights reached a maximum of 5 meters in the east of Japan and the east of Kanto.
On the 8th, high pressure moved over Honshu.
A front from the low pressure area near the Chishima Islands passed through the east of Japan and extended to the south of Japan, and the gradient of pressure between it and the high pressure system increased, causing waves to rise in the seas near Japan.
On the 9th, a low pressure system moved eastward over Primorye and settled west of Hokkaido.
From the 10th to the 11th, a low pressure system accompanied by a front moved westward from the Sea of Japan to Hokkaido.
The front moved southward over Honshu, and on the 10th waves rose in the western Japan Sea, East China Sea, south and east of Japan, and on the 11th in the central and northern Japan Sea and east of Japan.



#Sea surface temperature
Sea surface temperatures in the Japanese waters were significantly higher than normal, and were up to 5 C higher than normal on the western continental side.
The fairly high sea area gradually shrunk.
The East China Sea and the waters around the Nansei Islands were at normal levels.
To the south of Japan, waters slightly higher than normal have expanded.
From off the coast of the Tokai region to the south of the Kanto region, waters slightly lower than normal have expanded.
East of Kanto was slightly higher than normal.
Off the coast of Sanriku, the sea area continued to be lower than normal, with temperatures up to 4c lower.
The sea area around Hokkaido was normal, and the sea ice area in the sea near the Chishima Islands and the Sea of Okhotsk decreased.

Weather for today, the 16th (Thursday): The weather has improved near Honshu, and summer days are expected from Kanto to Kyushu

2026/04/16 09:03

Today, the 16th (Thursday), the low pressure system will move away from the sea east of Japan, and the weather will improve in many places. It looks like there will be some rain in the Kanto and Tohoku regions until the morning, but it is expected to gradually stop.

During the day, it is expected to be warmer than normal in many places, with some places from Kanto to Kyushu experiencing summer days with temperatures above 25c. The predicted maximum temperature is 25c in Tokyo and Hiroshima, and 27c in Nagoya, which is expected to be significantly higher than yesterday. You will be able to spend the day without needing a jacket.



However, the temperature difference between morning and night tends to be large, so please dress appropriately to keep yourself in shape. Additionally, as sunlight reaches from western Japan to eastern Japan, UV rays tend to be stronger, so it is a good idea to wear sunscreen and a hat.



In the inland areas of Kanto and southern Tohoku, atmospheric conditions will become unstable in the afternoon, with the possibility of sudden rain and thunderstorms. Please be aware of changes in the sky.

[Typhoon No. 4] Warning-level high waves are likely to occur in the Ogasawara Islands from around the 17th. Be careful of high waves with swells from western Japan to the Pacific side of eastern Japan.

2026/04/15 20:25

As of 6 p.m. today, Wednesday the 15th, Typhoon No. 4, a large and very strong typhoon, is moving slowly northwest near the Mariana Islands.

#Typhoon No. 4 15th (Wed) 6:00 pm
===================
Size Large
Power: Very strong
Center location: Mariana Islands
Movement speed: Northwest Slow
Central pressure: 935hP a
Maximum wind speed 45m/s (near the center)
Maximum instantaneous wind speed 65m/s
==================

Typhoon No. 4 will continue to move northward tomorrow, the 16th (Thursday), and is expected to gradually change its course to the east from the 17th (Friday).
Typhoon No. 4 is expected to move over the sea away from the Ogasawara Islands to the east, but it is expected to be accompanied by swells in the sea near the Ogasawara Islands tomorrow, the 16th. Around the 17th, waves are expected to reach a height of over 6 meters, and there is a risk that the waves will reach warning level until around the 18th. The wind is also expected to increase, so please be careful of strong winds.




Although areas near Honshu will not be directly affected by Typhoon No. 4, waves will be high along with swells along the Pacific coast of western Japan and eastern Japan. In the Izu Islands, it is expected that there will be some places where waves will be over 4 meters high tomorrow, the 16th. Please be very careful.

Tomorrow, the 16th (Thursday), the weather will improve from the west, with sunny spells spreading across the country and temperatures rising

2026/04/15 13:02

Today, the 15th (Wednesday), due to the influence of a front and humid air, it rained over a wide area from western Japan to eastern Japan, and it was a cloudy day even in northern Japan.
However, the weather will gradually improve from the west as the front moves away to the east and the anticyclone gradually strengthens through the night.

The weather is expected to improve across the country tomorrow, the 16th (Thursday), and temperatures are expected to rise in sunny areas.



Tomorrow morning, light rain may remain in parts of Hokkaido and the coastal areas of Tohoku and Kanto, but
the clouds will fade as time passes, and many areas will see clear skies before noon. Particularly in eastern and western Japan, blue skies are expected to spread out and plenty of sunlight will reach the area.
The temperature will rise during the day tomorrow, reaching around 20c in many places from Kanto to Kyushu, and the daytime will be sunny and comfortable even with a light jacket. In the Tohoku region, the number of places with temperatures exceeding 15 degrees Celsius is increasing, and the cold is easing.



The temperature will continue to be higher than or similar to normal. Also, the temperature difference between morning and daytime is large, so you need to be careful when choosing clothing.

The heat has eased, and temperatures are typical of this time of year in various parts of the country. There is a large difference in temperature throughout the day in northern Japan.

2026/04/15 06:57

Yesterday, the 14th (Tuesday), the weather was sunny and warm from eastern Japan to the Kinki region, and it was the first summer day in Osaka in two weeks since March 31st. In addition, the temperature in central Tokyo reached 24.6c, which is unseasonably warm and just one step away from summer.



Today, the 15th (Wednesday), will be a day with little sunshine, with cloudy and rainy conditions from eastern to western Japan due to the influence of low pressure and fronts. The heat of the previous day will ease, and temperatures in various places will reach a maximum of around 20 degrees Celsius, which is typical for this time of year. It seems to be a relatively relaxing place.
On the other hand, sunlight is expected to reach northern Japan around mid-morning. During the day, temperatures are expected to reach mid-May temperatures in some places in the Tohoku region, and there will be a large difference in temperature between morning and evening and during the day. Please be careful not to get sick due to the temperature difference.

The predicted maximum temperature is Sapporo 15c, Sendai 17c, Tokyo 21c, Nagoya 19c, Kanazawa 18c, Osaka 19c, Kochi 20c, and Fukuoka 18c.