Three-day weekend weather: Hokkaido is at risk of heavy rain due to the path of a front and low pressure system; Western and eastern Japan should be careful of sudden weather changes and dangerous heat

2026/07/18 07:45

I think many people will have a three-day holiday from today, the 18th (Sat) to tomorrow, the 20th (Mon). During the three-day holiday period, there is a risk of warning-level heavy rain in Hokkaido and northern Tohoku.



Around Honshu, extremely warm and humid air flows in around the edge of the high pressure system in the south of Japan, making the atmospheric conditions unstable. Also, from the west, a front and a low pressure system above the front are expected to move near the Sea of Japan.
As warm, humid air flows towards the front and low pressure, the total rainfall will increase mainly in Hokkaido, which is the path of the front and low pressure, and there is a risk of warning-level heavy rain. Even in the northern Tohoku region, there are likely to be some places where there will be heavy rain accompanied by localized thunderstorms.
Please be careful of landslides, flooding of low-lying land, flooding of roads, rising water levels and flooding of rivers, and check the latest weather information that will be updated during the holidays.

From southern Tohoku to Kyushu, the effects of warm, humid air and rising daytime temperatures will likely lead to unstable skies, especially inland and along the mountains. Even in places where there is no umbrella symbol in the weather forecast, be careful of sudden rain or thunderstorms. In addition, due to heavy rains so far, the ground may be loose and rivers may be swollen in some places, so please continue to be careful of landslides, flooding of low-lying areas, and flooding of roads.
If you are planning to enjoy leisure activities in the mountains or rivers during the holidays, if you see black clouds or hear thunder, there is a high possibility that the weather will suddenly change, so please pay attention to changes in the sky and take precautions such as taking shelter in a sturdy building.

Also, be careful of the dangerous heat. In many places, it will be hotter than normal and the humidity will be high, making it feel humid in many places. Temperatures will not drop much during the day as well as at night, and many places in western and eastern Japan are expected to experience tropical nights. You need to be careful about heatstroke day and night, and please take all possible measures to prevent heatstroke, such as staying hydrated frequently and actively using the air conditioner even at night.

There is a fear that a linear rain band will form in southern Gunma Prefecture and southern Tochigi Prefecture within the next 3 hours, and the risk of heavy rain disasters will rapidly increase.

2026/07/17 22:34

At around 9:50 p.m. today, Friday, the 17th, the Japan Meteorological Agency announced a near-strike forecast for a linear precipitation band, targeting southern Tochigi and southern Gunma prefectures, stating that there is a risk that a linear precipitation band will form within the next three hours and extremely heavy rain will continue.

As of 10:00 pm on the 17th (Friday), well-developed rain clouds can be seen in places in the Kanto-Koshin region, and extremely well-developed rain clouds are hanging over the prefectural borders of Gunma, Tochigi, and Saitama prefectures in the northern Kanto region. At 9:40 p.m., heavy rain was observed in Kiryu City, Gunma Prefecture, with an hourly rainfall of 38.0 mm, and heavy rain was observed at multiple locations in Gunma Prefecture and Tochigi Prefecture.
Currently, there are places in Gunma and Tochigi prefectures where level 4 heavy rain danger warnings and landslide danger warnings have been announced.

If linear precipitation bands occur in the future, the risk of life-threatening heavy rain disasters will rapidly increase. Please be extremely cautious of landslides, flooding of low-lying areas, rising water levels and flooding of rivers, etc.

Please avoid approaching dangerous areas such as rivers and cliffs, and take appropriate evacuation actions in accordance with evacuation information issued by local governments. If it is difficult to evacuate, please try to ensure your safety by moving to a higher place such as the second floor of your home or higher.

Weather for tomorrow 18th (Saturday): Rainy holidays start in eastern and northern Japan

2026/07/17 17:34

A low pressure system accompanied by a front is expected to move through the Yellow Sea.



Tomorrow, the start of the three-day holiday, looks like the weather will not be refreshing in eastern and northern Japan.
A front extending from the Sea of Japan is expected to approach northern Japan. Rain will fall mainly on the Sea of Japan side of northern Japan, and the area of rain will gradually expand to the east. Localized heavy rain and thunderstorms are possible at night.
In eastern Japan, clouds are likely to spread, and there is a possibility of showers in places. Don't forget your umbrella when you go out. Even if there is little sunlight, the humidity is high and the weather is likely to be unpleasantly hot.
Western Japan has many areas that receive sunlight, and it continues to be extremely hot. In Kyushu, there are likely to be some extremely hot days with temperatures exceeding 35 degrees Celsius during the day. There is a chance of showers in the afternoon, mainly along the mountains.

[Kanto Level 4 Heavy Rain Danger Warning Announced] Be careful of sudden changes in weather even during the holidays! (Commentary: Weather forecaster Atsuko Miyake)

2026/07/17 15:04

The atmospheric conditions in the Kanto region have been unstable since this morning, with thunderstorms occurring here and there.



Looking at the state of the rain clouds at 2:00 p.m., active rain clouds are scattered here and there in the Kanto region, and lightning strikes have also been observed.

In Hachioji City, Tokyo, extremely heavy rain of 58.5mm was observed in the hour until 2pm.



As of 2:00 p.m., a level 4 heavy rain danger warning has been issued for Hachioji City in Tokyo, Matsudo City, Chiba Prefecture, Ichikawa City, Yokohama City, and Kawasaki City in Kanagawa Prefecture.
If you are in a dangerous place, please assess your surroundings and immediately evacuate to a safe place.

As the atmosphere continues to be unstable, please be careful of sudden changes in the weather, even in places where it is not raining right now.
Be careful of lightning, tornadoes, strong wind gusts, and hail.



Now, let's take a look at the forecast for rain clouds.
After this, rain and thunderstorms are expected to occur over a wide area.
Also, the wind that carries the rain clouds is weak today, so even if rain clouds form, there is a possibility that extremely heavy rain will continue to fall in similar areas.


After this, there is a possibility that rain will continue in similar places in the northern Kanto region, such as around Utsunomiya,
through the night.

Also, the date has changed and rain clouds will continue to remain from early morning to early morning tomorrow (Friday), and
there is a risk that it will continue to rain heavily in similar areas.



In urban areas, if it continues to rain in the same area, drainage may not be able to catch up and rainwater may flow into
underpasses.

Today, please stay away from underground facilities and other places where rainwater can easily enter.

Also, lightning strikes are occurring, so please move to a sturdy building to protect yourself.

For information such as when the rain clouds will leave, please check the latest information on the rain cloud radar.



I think many people will have a three-day weekend starting tomorrow the 18th (Saturday), but it seems that there are few days in the Kanto region that are tightly covered by high pressure even during the holidays.

Moist air flows towards the front in the Sea of Japan.
The Kanto region continues to be prone to clouds and rain clouds.

There will still be rain and thunderstorms in the plains, especially tomorrow the 18th (Saturday), so please bring rain gear when you go out.

In the latter half of the holidays, there will be periods of sunshine, but thunderstorms are more likely to occur along the mountains.
Please be careful of sudden changes in weather when enjoying leisure activities in the mountains and rivers.



In the Kanto region, it is likely to rain during the first half of the holidays.
On the 18th (Saturday), there will be rain and thunderstorms even in areas marked cloudy, so
Please be aware of sudden changes in the weather.

The latter half of the holidays is likely to be sunny in the southern Kanto region, but the temperature will rise as the second half progresses.
Please be careful of heat stroke.



Weekly forecast.
The Kanto region will be marked as sunny from now on.
The rainy season has not yet ended in the Kanto-Koshin region, but I think there will be an announcement about the end of the rainy season soon.
However, once the rainy season ends, the heat will increase even more.
Inland areas are expected to continue experiencing extremely hot days with temperatures above 35c starting from the middle of next week.
The temperature will be quite high. Please be even more careful about heatstroke than ever before.

[3-day weekend weather] Atmospheric instability - Be careful of sudden changes in leisure weather in mountains and rivers! Warning heavy rain in Hokkaido (Commentary: Weather forecaster Atsuko Miyake)

2026/07/17 13:54

Atmospheric conditions have been unstable since the morning of today, the 17th (Friday).
Looking at the state of the rain clouds at noon, there are heavy rain clouds scattered here and there from the Kanto region to the Tohoku region.



Lightning has also been observed in the central Kanto area.
After this, in the afternoon, there is a high probability of lightning occurring not only in the Kanto and Tohoku regions, but also around the Kyushu region.

Please be careful of sudden changes in the weather from now on, even in areas where the weather is sunny now.
Please be careful of sudden strong rain, lightning strikes, strong gusts of wind such as tornadoes, and hail.



This is the forecast for rain clouds after this.
Towards the evening, rain clouds are expected to develop not only along the mountains in the Kanto, Tohoku, and Kyushu regions, but also
on the plains.

The wind that carries the rain clouds is quite weak today, so once the rain clouds develop,
it is expected to continue raining in the same places.

Rain clouds will clear up in the Tohoku and Kyushu regions at night, but in the Kanto region, rain is expected to continue in similar areas into the night.



There is a risk of heavy rain and thunderstorms in similar areas into the early hours of tomorrow.
Please be careful about flooding of roads and low-lying land.




Also, I think many people will have a three-day weekend starting tomorrow the 18th (Saturday), but it seems like it will be difficult to have clear skies even during the holidays because of the high pressure.

There are fronts and low pressure systems in the Sea of Japan, and the area around Honshu is a path for moist air.
Tomorrow, the 18th (Saturday), there will be a lot of clouds, and there are likely to be showers and thunderstorms here and there.
Please bring rain gear when going out.

There is a risk of warning-level heavy rain in Hokkaido from the 19th (Sunday) to the 20th (Monday/Holiday) as the low-pressure front approaches.
In Hokkaido, the ground has become loose due to past rains, so please be careful and be on guard against landslides.



This is the weather during the 3-day holiday.
It continues to rain in Hokkaido during the holidays.
Please be careful of heavy rain, especially from the 19th to the 20th.
Also, it tends to rain more in Tohoku and Hokuriku during the first half of the holidays.

Toward the latter half of the holidays, there will be some sunny days in western and eastern Japan, but
thunderstorms are also likely to occur along the mountains, so
please be careful of sudden changes in the weather when enjoying leisure activities in the mountains and rivers.



Weekly forecast. Next week. The sunny mark stands out.

In eastern Japan, such as the Kanto-Koshin region, and in the Tohoku region,
there is no announcement yet that the rainy season will end, but it looks like the end of the rainy season will increase in many places next week.



It looks like it will be quite hot from the middle of next week.
``Early weather information regarding high temperatures'' has also been announced, and from around the 22nd (Wednesday), it is likely to be ``very high temperatures'' nationwide.

For this time of year. There is a risk that the temperature will reach a level that occurs only once every 10 years.
Raise your precautions next week by one step higher than your previous precautions against heat stroke.

[Marine Summary] Severe drowning near the Nansei Islands due to Typhoon No. 9 (July 5th to 11th, 2026)

2026/07/17 13:39

Typhoon No. 9 was the most powerful and ferocious typhoon in the Mariana Islands.
After that, a large and strong force passed near the Sakishima Islands.
The sea near the Nansei Islands was severely flooded, with wave heights reaching a maximum of 13 meters when the typhoon passed.
Below is a summary of the ocean (July 5th to 11th, 2026)



#Pressure distribution and waves
On the 6th, a large and ferocious typhoon No. 9 moved westward near the Mariana Islands, and on the 7th and 8th it moved westward east of the Philippines with extremely strong force.
On the 9th, Typhoon No. 9, a large and very strong typhoon, changed its course to the northwest east of the Philippines, and reached the south of Okinawa on the 10th.
On the 11th, Typhoon No. 9 was large and powerful, passing near the Sakishima Islands and moving northwest.
As Typhoon No. 9 approached Japan, waves were rough in the south of Japan and near the Ogasawara Islands on the 7th and 8th, and waves were slightly higher in the east of Japan.
From the 8th to the 9th, there was a storm in the sea near the Nansei Islands, and in the south of Okinawa and the south of Japan, there was a severe storm around the typhoon.
From the 10th to the 11th, the sea near the Nansei Islands was hit by a typhoon, resulting in severe flooding, with wave heights reaching a maximum of 13 meters.



#Sea surface temperature
Sea surface temperatures in the Japanese waters continued to be higher than normal.
The temperature gradually rose significantly above normal, mainly in the central part of the country, reaching a maximum of 3 C above normal.
The East China Sea, the waters near the Nansei Islands, and the south of Japan remained at normal levels, while the waters off the southeastern coast of Kanto continued to be slightly lower than normal.
Off the coast of Sanriku, conditions continued to be at normal levels.
Off the southeastern coast of Hokkaido, sea areas continued to be significantly higher than normal, with temperatures up to 4 C higher than normal.
In the waters near the Kuril Islands, the area slightly below normal has shrunk.
The Sea of Okhotsk was slightly higher than normal.

Today's weather (Friday 17th): The atmosphere is unstable nationwide. Be careful of sudden heavy rain and thunderstorms. The Tokai Kinki region is experiencing intense heat.

2026/07/17 07:58

Atmospheric conditions will be unstable over a wide area today, the 17th (Friday). Please be aware of sudden and severe thunderstorms in places, especially in the afternoon.
It will be hot and humid in many places, so please continue to take precautions against heat stroke.



Today, the weather is likely to be cloudy in many places, and rain clouds are likely to form in some parts of the Kanto region during the morning commuting hours. In the afternoon, rain clouds will appear here and there, mainly in Kyushu, Kanto-Koshin, and Tohoku, and there will be places where it will rain heavily, accompanied by thunder. In eastern Japan, rain will continue into the night.



The probability of lightning strikes is high in Kyushu and eastern Japan from late afternoon to evening, and in Kanto and Koshin areas even into the night. In some places in eastern Japan, it's more than 50%. If the sky suddenly becomes dark or you hear the sound of thunder nearby, please move to a safe place.


There are some places where the sun shines, and the temperature rises during the day, making it extremely hot. Temperatures are expected to rise to 34c in Asahikawa, Hokkaido, where it is sunny, and 32c in Sapporo.
It will be extremely hot in the Tokai and Kinki regions, with Kyoto at 37 degrees Celsius, and places like Osaka and Gifu at 36 degrees Celsius, which is likely to be as hot as body temperature. The humidity will be high and the heat will be uncomfortable, so please take care of your health.

From around July 22nd, dangerous heat of "once in 10 years" will be felt all over the country, so be on guard against heat stroke!

2026/07/17 06:48

Yesterday, the 16th, the Japan Meteorological Agency announced "early weather information regarding high temperatures" for Hokkaido, Kyushu, Amami, and Okinawa.



"Early weather information regarding high temperatures" is announced when the region is expected to experience high temperatures that are at a once-in-a-decade level for this time of year.
The Japanese archipelago will be more likely to be covered in warm air from now on, so it is expected that there will be many days with ``fairly high temperatures'' over the next two weeks.
Extremely high temperatures are expected from Hokkaido to Kyushu and Amami from around the 22nd (Wednesday), and in Okinawa from around the 25th (Saturday). In addition to taking care of your health, please also be careful about managing your crops.



Next week, temperatures inland are expected to be just one step away from being extremely hot, with maximum temperatures reaching 40c. It looks like the rainy season will end next week in the Kanto-Koshin and Tokai regions.
The risk of heat stroke also increases. In particular, when a heatstroke warning alert is announced, please take proactive measures to prevent heatstroke, such as drinking plenty of water and salt, and avoiding prolonged outdoor activities and using an air conditioner indoors.

[Breaking news] New tropical cyclone develops and becomes typhoon No. 12

2026/07/16 17:45

According to information released by the Japan Meteorological Agency at 16:15 on the 16th, a new tropical cyclone has formed near the Truk Islands.
If this tropical cyclone develops, it is expected to become Typhoon No. 12.



The central pressure is 1006 hPa and it is moving east-northeast at 15 km/h. The maximum wind speed near the
center is 15 m/s, and the maximum instantaneous wind speed is 23 m/s.

At 3pm on the 17th, it is expected to proceed northeast at 15km/h near the Truk Islands, and at 3pm on the 18th, it will change course to the north and proceed at 10km/h.

Please check the latest information regarding your future career path.

Weather for tomorrow 17th (Friday): There is a risk of thunderstorms in Kanto and Tohoku

2026/07/16 17:35

Moist air is expected to flow around the edge of the high pressure system over the east coast of Japan. A front is expected to extend from the continent to the vicinity of the Korean Peninsula.



Clouds tend to spread in the Kanto, Hokuriku, and southern Tohoku regions due to the influence of humid air, and the weather is likely to be unrefreshing. There is a chance of rain and thunderstorms in places.
There is a risk of thunderstorms in Kyushu and western China due to the front, so please bring an umbrella when going out.
In eastern China, Shikoku, Kinki, Tokai, northern Tohoku, and Hokkaido, there are places where the sun can reach, and the intense heat continues. Please take all possible precautions against heatstroke, such as frequently drinking water and salt, taking adequate breaks, and using a parasol or hat when engaging in outdoor activities.