Latest One-Month Forecast: Sunny Days Expected in October; Warmer Than Average with a Slow Seasonal Progression

2026/10/01 17:54

On Thursday the 1st, the Japan Meteorological Agency released its latest one-month forecast, outlining expected weather conditions for the coming month.



Sea-level pressure near Japan is expected to remain higher than average in the coming period. Consequently, the region is likely to experience relatively frequent days under the influence of high-pressure systems. However, a pressure trough is forecast to form north of Hokkaido; as a result, Northern Japan may be susceptible to the effects of weather fronts and low-pressure systems during the latter half of the period.

Temperatures at an altitude of approximately 1,500 meters are expected to be higher than average across Northern, Eastern, and Western Japan, with the region likely to be covered by warm air.

Weather conditions are expected to fluctuate in cycles lasting a few days. However, there will likely be more sunny days than usual, and precipitation is forecast to be below average, particularly along the Pacific coast. While some areas in the Kanto region experienced record-breaking heavy rainfall in September, October is expected to see a shift toward fewer rainy days.
In Western Japan, continued caution regarding water management is advised for areas currently experiencing water shortages.



Average temperatures are expected to trend higher than normal, suggesting a slow progression of the seasons. Although the leaves on high-altitude mountains across Honshu will begin to change color in the latter half of October, the peak of the autumn foliage season is likely to arrive later than usual.
However, as this is a time of year when significant temperature differences between day and night are common, please be mindful when choosing your daily attire to avoid falling ill. In the Okinawa and Amami regions, surface air temperatures are expected to be high due to the influence of high sea-surface temperatures.

A front is passing through northern Japan; beware of thunderstorms. Cold air is expected to flow in tomorrow, the 2nd, bringing colder temperatures.

2026/10/01 12:09

Today, Thursday, a low-pressure system accompanied by a front is expected to pass through the area stretching from Primorsky Krai to the Strait of Tartary. A cold front will move across Hokkaido and northern Tohoku, causing the area of ??rainfall to gradually shift eastward. Please be alert for sudden thunderstorms.



Rain clouds associated with the cold front currently cover parts of Hokkaido and Aomori Prefecture, bringing heavy downpours to some areas.
In Imakane (Imakane Town, Setana District, Hiyama Region, Hokkaido), 23.5 mm of heavy rain was recorded in the hour leading up to 8:08 AM, setting a new record for the highest hourly rainfall for October in that location.



The rain clouds are expected to move gradually eastward from here on. As the cold front passes, some areas may experience localized heavy rain accompanied by thunder. Please be cautious of lightning strikes and sudden gusts of wind.



The low-pressure system is forecast to intensify as it moves into the Sea of ??Okhotsk by tomorrow, Friday. The pressure gradient around Hokkaido will steepen, leading to stronger winds; please be on the alert for strong winds and high waves.

Additionally, cold air is expected to flow into the upper atmosphere as the front passes. Tomorrow, Friday the 2nd, clouds will likely spread across Northern Japan?particularly along the Sea of ??Japan coast?bringing rain to some areas. Some mountainous regions might even see their first snowfall of the season.
Temperatures will drop compared to today, Thursday the 1st; highs are forecast to reach 14C in Asahikawa and 18C ??in Sapporo. With lows hovering around 10C, it will feel chilly in many places. Please adjust your clothing accordingly and take care to stay healthy.

Typhoon 27 (Choi-wan) Forms; First Typhoon of the Month

2026/10/01 06:50

At 3:00 a.m. today, October 1, a developing tropical depression in the Mariana Islands intensified into Typhoon No. 27. This is the first typhoon to form this month.

As of 3:00 a.m., Typhoon No. 27 is located in the Mariana Islands and is moving west-northwest at a speed of approximately 15 km/h.

? Typhoon No. 27 ? 3:00 a.m., Thursday, the 1st
==================
Center Location: Mariana Islands
Movement: West-northwest at 15 km/h
Central Pressure: 998 hPa
Max. Wind Speed: 18 m/s (near center)
Max. Instantaneous Wind Speed: 25 m/s
==================



The typhoon is expected to continue intensifying as it moves in a westerly direction. It is forecast to shift its course toward the north around Saturday, the 3rd, and continue moving northward on Sunday, the 4th, while accompanied by a zone of gale-force winds. There is a risk that the storm will approach the Ogasawara Islands with considerable strength around the 6th; please stay updated on the latest typhoon information, as impacts from wind and rain are a concern.

Weather for today, Thursday: Watch out for thunderstorms in Hokkaido; brief showers in southern Kanto until morning; mostly sunny during the day.

2026/10/01 06:25

As we begin October today (Thursday), a front is expected to pass near Northern Japan. Additionally, Typhoon No. 26 is forecast to pass near Aogashima and move away to the east of Japan.



In Northern Japan, the area of ??rainfall is expected to shift across the region.
Rain is likely on the Sea of ??Japan side of Hokkaido until around midday, while the northern Tohoku region and the Pacific side of Hokkaido will see rain starting in the early afternoon. Some areas may experience heavy rain accompanied by thunder, so please be cautious of lightning strikes and sudden gusts of wind. It is advisable to carry rain gear when going out. Please also be mindful of temperature changes, as colder air will flow in after the front passes.

While many areas along the Sea of ??Japan?stretching from southern Tohoku and Hokuriku to the Chugoku region?will see sunny skies, there is a possibility of passing showers in the afternoon, so carrying a folding umbrella is recommended.

In the Kanto region, scattered showers are likely, mainly in southern areas, until the morning.
Conditions are expected to improve in many areas by the afternoon. Temperatures will rise in many places compared to yesterday, so please take care of your health.

From the Tokai region through Western Japan, sunny skies are expected to prevail throughout the day. Temperatures will reach around 30C in many areas, creating conditions where you might break a sweat if active; please take precautions against heatstroke.

Weather and Temperature Summary (September 20–26): Typhoon No. 25 Approaches — Record-Breaking Heavy Rain in Southern Kanto; First Sub-Freezing Temperatures of the Year in Hokkaido.

2026/09/30 21:30

Here is a summary of the weather and temperatures from September 20 to September 26, 2026.


? Characteristics of Pressure Patterns
On the 20th, a large, strong Typhoon No. 25 moved north-northeastward south of Japan, while a low-pressure system accompanied by a front moved eastward across the Primorsky Krai region. On the 21st, the large, strong Typhoon No. 25 moved northward south of Japan and then northeastward over the waters east of the Kanto region. On the 22nd, Typhoon No. 25 transformed into an extratropical cyclone and moved northeastward east of Japan; a high-pressure system extended from the Asian continent, covering the area around Japan. On the 23rd, a low-pressure system formed off the Kii Peninsula and moved eastward off the Tokai region. On the 24th, the low-pressure system moved from off the Tokai region to the waters east of Kanto. A front extended from the northern Sea of ??Japan, through the Sea of ??Okhotsk, to the vicinity of the Kuril Islands; a low-pressure system formed on the front at 09:00, and the associated front passed over Hokkaido. On the 25th, the center of a migratory high-pressure system moved southeastward across the Sea of ??Japan, creating a pressure pattern with higher pressure to the north of Honshu. A low-pressure system formed on a front in central China and moved eastward, while Typhoon No. 26 moved northwestward south of Okinawa. On the 26th, an autumn rain front extended from the continent through northern Kyushu and Shikoku to the southern coast of Honshu, with a low-pressure system on the front moving eastward across the Yellow Sea; Typhoon No. 26 moved north-northwestward south of Okinawa.

? Precipitation
On the 20th, a band of precipitation covered the area from south to east of Japan, with analysis indicating strong to heavy rainfall; heavy rain also occurred in the Hokkaido region due to the passage of a low-pressure system. On the 21st, Typhoon No. 25 approached the Kanto-Koshin region. Active rain clouds covered areas primarily along the Pacific coast from the Tohoku region through Eastern Japan; torrential rain was recorded in the Izu Islands, while very heavy rain was observed in the Kanto and Tokai regions. On the 22nd, the weather shifted abruptly from the clear skies that followed the typhoon's passage; localized rain clouds developed along the southern coast of Kanto and in the mountainous areas of Shizuoka Prefecture. On the 23rd, influenced by a low-pressure system moving east off the coast of Tokai, skies were mostly cloudy across Eastern Japan, with intermittent rain in southern Kinki and the Kanto area. Moderately heavy rain was recorded in southern Chiba Prefecture and Wakayama. On the 24th, rain clouds passed over Hokkaido as a front moved through; the rainfall intensified as the front passed, resulting in heavy rain. Rain also fell in Tohoku and northern Kanto during the early morning hours. On the 25th, rain clouds associated with a localized front developed near the Izu Islands, and torrential rain was briefly recorded on Miyake-jima. On the 26th, the area of ??precipitation near the front expanded from the pre-dawn hours through the morning, with heavy rain observed in Ibaraki, Tochigi, and Chiba prefectures.


? Temperatures
On the 20th, sunny skies along the Pacific coast of Western Japan caused temperatures to rise, resulting in a "midsummer day" (highs of 30C or above). Eastern Japan remained cloudy, which suppressed the rise in temperature. On the 21st, limited sunshine across the region from Tohoku to Tokai resulted in sluggish temperature increases. However, temperatures rose in western Tokai and along the Pacific coast of Western Japan as northerly winds descended the mountains (foehn effect). On the 22nd, temperatures rose along the Pacific coast; central Tokyo recorded a high above 30C for the first time in eight days, marking a midsummer day. On the 23rd, sunny skies prevailed mainly in Western Japan, bringing intense lingering summer heat. The Kanto area remained cloudy or rainy, with central Tokyo's maximum temperature of 24.6C recorded during the early morning hours. On the 24th, sunshine returned to Tohoku and Kanto, and clear, sunny weather extended across a wide area from Tohoku to Western Japan. Temperatures in the Kanto region rose significantly compared to the previous day; central Tokyo recorded a high of 29.8C, an increase of 5.2C. On the morning of the 25th, Numakawa in Wakkanai City, Hokkaido, recorded a low of -0.4C?the season's first "winter day" (a day with a minimum temperature below 0C). During the day, lingering summer heat persisted in western Japan, with "midsummer days" (highs of 30C or above) recorded, particularly in Kyushu. On the 26th, widespread cloud cover kept temperatures from rising sharply, though midsummer-level heat was still observed in southern Kyushu.



? Summary of Weather Conditions (September 20?26)
Average temperatures were generally near or slightly above normal across the country, influenced by warm, humid air from typhoons and periods of high-pressure dominance. Areas stretching from the Pacific side of Tohoku and eastern Japan to the Pacific side of western Japan saw temperatures approximately 2C above normal.
Precipitation levels were above normal from the Pacific side of Tohoku down to southern Kanto due to the influence of Typhoon No. 25, with record-breaking heavy rainfall in Chiba and Kanagawa prefectures. Central Tokyo received more than five times the normal amount of rainfall for the period, and weather warnings were issued in various locations.
Sunshine duration was near or slightly below normal across the region from Tohoku to Kinki, areas affected by typhoons and humid air. Conversely, Hokkaido, northern Tohoku, and the area spanning Chugoku/Shikoku to Kyushu saw minimal impact, experiencing sunshine levels that were near or slightly above normal.

[Latest Typhoon Information] Typhoon No. 26 (Surigae) may approach the Kanto region on Thursday the 1st; please be alert for strengthening winds in the Izu Islands and coastal areas.

2026/09/30 18:11

During the first half of the period, Typhoon No. 25 moved north-northeastward south of Japan, transforming into a tropical depression and subsequently into an extratropical cyclone. Due to this typhoon, rough sea conditions (high waves) occurred around the Izu Islands.
During the second half of the period, Typhoon No. 26 formed and moved north-northwestward south of Japan, causing rough seas in parts of the Nansei Islands area.

Sea surface temperatures in waters near Japan showed an expansion of areas where temperatures were above normal; notably, waters southeast of Hokkaido reached temperatures up to 4C higher than average.

Summary of Ocean Conditions (September 20-26, 2026)



Pressure Patterns and Waves
On the 20th, Typhoon No. 25 moved northwestward south of Japan, causing wave heights to rise across a wide area of ??the Pacific coast; rough seas with wave heights around 4 meters were observed from the waters off Shikoku to the waters off the Kanto region. On the 21st, Typhoon No. 25 intensified while moving northeastward south of Japan and passed over the waters south of Kanto. Rough seas with wave heights around 7 meters occurred around the Izu Islands. From the 22nd to the 23rd, Typhoon No. 25 moved northwestward off the Sanriku coast and transformed into an extratropical cyclone. From the 23rd to the 25th, high pressure covered a wide area from Northern to Western Japan, resulting in calm wave conditions. On the 24th, a tropical depression south of Japan intensified into Typhoon No. 26. From the 24th to the 26th, Typhoon No. 26 moved north-northwestward south of Japan, causing rough seas with wave heights around 4 meters near the Nansei Islands on the 26th.



Sea Surface Temperature
In the waters surrounding Japan, the area with temperatures slightly above normal expanded. Temperatures in the East China Sea and around the Nansei Islands remained near normal, though areas with slightly above-normal temperatures began to appear near the Nansei Islands during the latter half of the period. Conditions off the coasts of Shikoku and Tokai remained near normal, consistent with the previous week. East of the Kanto region, the area with slightly above-normal temperatures expanded. Off the Sanriku coast, the area with slightly below-normal temperatures shrank. Off the southeastern coast of Hokkaido, the area with above-normal temperatures expanded, reaching a maximum of 4C above normal. Areas with slightly above-normal temperatures also expanded in the waters near the Kuril Islands and in the Sea of ??Okhotsk.

Typhoon No. 26: Risk of rough weather from the Izu Islands to the Kanto coast today and tomorrow.

2026/09/30 14:15

As of 9:00 a.m. on the 30th, Typhoon No. 26 is moving eastward over the waters south of Japan at a speed of approximately 15 kilometers per hour. Its central pressure is 996 hectopascals, with maximum sustained winds of 20 meters per second and peak gusts of 30 meters per second.



The typhoon is expected to pass very close to the Izu Islands between the early evening of the 30th and the early morning of October 1st.
Rain clouds are also expected to affect the Miura Peninsula and the vicinity of Chiba Prefecture from late morning through the evening of October 1st.

Due to the typhoon itself and associated developed rain clouds, atmospheric conditions will become highly unstable over a wide area.
Consequently, areas experiencing heavy to very heavy rain accompanied by thunderstorms are expected in the southern Izu Islands through the early morning of October 1st,
and in Kanagawa and Chiba Prefectures from late morning through the evening of October 1st.

Depending on the typhoon's path and intensity, there is a possibility of heavy rainfall reaching warning levels.
As the ground has already been loosened by previous rainfall, please remain on high alert for landslides.



With the approach of Typhoon No. 26, caution and vigilance are required regarding landslides in the Izu Islands from the evening of the 30th through the late morning of October 1st,
and regarding high waves accompanied by swells in the southern Izu Islands from late at night on the 30th through the morning of October 1st. Please also be alert for strong winds, lightning strikes, and violent gusts such as those associated with tornadoes.



[Wave Forecast]
Rough seas accompanied by swells are expected in the southern Izu Islands from the evening of the 30th through the morning of October 1st.
Forecast wave heights (30th ? October 1st):
Northern Izu Islands: 3 meters (with swells)
Southern Izu Islands: 5 meters (with swells)

Depending on the typhoon's path and intensity, seas could become very rough.
Please stay updated with the latest information.

[All-Time Record Broken] Precipitation Observed in Tokyo for 35 Consecutive Days; Rain Every Day in September

2026/09/30 07:26

Rain continues to fall in central Tokyo today, Wednesday the 30th, extending the streak of consecutive days with precipitation to 35 days, dating back to August 27th.



As of yesterday, Tuesday the 29th, the streak had already surpassed the previous record of 33 days set in 2019 (June 27?July 29), marking the longest such period in 150 years. This means central Tokyo has experienced rain almost every day for over a month.



Intermittent rain has continued in Tokyo since the early hours of today, Wednesday the 30th. Consequently, the record has been extended further, reaching 35 consecutive days of precipitation.
This means precipitation was recorded every single day in September; it is the first time in recorded history that rain has been observed daily throughout the entire month of September in central Tokyo.

The Kanto region remains under the influence of an autumn rain front today, so unsettled weather with a high likelihood of rain is expected to continue throughout the day.



Additionally, as Typhoon No. 26 approaches the Izu Islands, winds are expected to strengthen from the evening onwards, potentially leading to rough weather conditions. In the southern Kanto region, rain is likely?particularly along the southern coast?through the morning of tomorrow, Thursday the 1st.
Rain is also forecast for Chiba and Kanagawa prefectures, which recently sustained significant damage from Typhoon No. 25. Even a small amount of rain necessitates caution against landslides and other related disasters.

[Latest Typhoon Information] Typhoon No. 26 (Surigae) may approach the Kanto region on Thursday the 1st; please be alert for strengthening winds in the Izu Islands and coastal areas.

2026/09/29 22:19

As of 9:00 PM today, Tuesday the 29th, Typhoon No. 26 is located over the ocean south of Japan, moving east-northeast at a speed of 20 km/h. Its central pressure is 994 hPa, with maximum sustained winds of 23 m/s near the center and maximum instantaneous wind gusts of 35 m/s.

Typhoon No. 26 As of 9:00 PM, Tuesday the 29th

Center location: South of Japan
Movement speed: East-northeast at 20 km/h
Central pressure: 994 hPa
Max. sustained wind: 23 m/s (near center)
Max. instantaneous gust: 35 m/s


Typhoon No. 26 is expected to pass near the Izu Islands between the evening of the 30th (Wednesday) and the 1st (Thursday). Rough to very rough seas are anticipated around the Izu Islands. Caution is advised, as conditions are likely to deteriorate?with intensifying wind and rain?from the evening onwards.

In the Kanto region, rain is likely to become widespread on the 30th (Wednesday), particularly in southern and eastern areas. As Typhoon No. 26 moves northward south of Japan, the autumnal rain front?currently stalled south of Honshu?will remain active. There is a possibility of localized thunderstorms and intensifying rainfall.
Subsequently, Typhoon No. 26 is expected to move across the waters southeast of the Kanto region. Stronger winds are likely in coastal areas. As it is a relatively compact typhoon, the area affected by rain clouds will be primarily in the south, while some northern areas may see sunshine. For those in Chiba and Kanagawa prefectures who are currently engaged in recovery efforts following the significant damage caused by Typhoon No. 25, please exercise the utmost caution regarding the wind and rain accompanying the approach of Typhoon No. 26.

[Typhoon Information] Typhoon No. 26 to make closest approach to Izu Islands tomorrow, Wednesday (30th); risk of stormy weather in the region.

2026/09/29 12:26

As of 9:00 a.m. today, Tuesday the 29th, Typhoon No. 26 is moving northeast at a slow pace over the waters south of Japan.

#Typhoon No. 26 ? As of 9:00 a.m., Tuesday the 29th
====================================
Center location: South of Japan
Movement speed: Northeast at 15 km/h
Central pressure: 990 hPa
Max. wind speed: 30 m/s (near the center)
Max. instantaneous wind speed: 40 m/s
====================================

Typhoon No. 26 is expected to continue moving in an easterly direction at a slow pace, making its closest approach to the southern Izu Islands late tomorrow night, Wednesday the 30th.
It is forecast to move out over the waters east of Japan the day after tomorrow, Thursday the 1st, and to transform into an extratropical cyclone as it moves away from Japan on Friday the 2nd.



In the Izu Islands, wave heights accompanied by swells will gradually increase starting tomorrow, the 29th; Hachijojima, in the southern Izu Islands, is expected to experience rough seas with swells. Additionally, very strong winds and heavy rainfall are likely. Please remain alert and cautious regarding strong winds, high waves accompanied by swells, and heavy rain-related disasters such as landslides; also, be on the lookout for lightning and violent gusts, including tornadoes. Additionally, as warm, moist air from the typhoon flows into the vicinity of the autumn rain front, rainfall is expected to intensify?particularly along the Pacific coast of Eastern Japan?from tomorrow, the 30th (Wednesday), through the day after, the 1st (Thursday). Heavy rain is a particular risk around Chiba Prefecture on or around the 1st, when Typhoon No. 26 is expected to make its closest approach to the Boso Peninsula.
It is important to note that some areas have yet to fully recover from the heavy rain damage caused by the previous Typhoon No. 25. Furthermore, the ground in some locations is likely already unstable due to recent rainfall. Please remain vigilant against heavy rain-related disasters?such as new landslides?even with relatively low rainfall, and be sure to check the latest weather updates as they become available.