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.

[Rain for 34 Consecutive Days] Tokyo AMeDAS records precipitation for 34 days in a row, setting a new all-time record.

2026/09/29 11:18

Tokyo AMeDAS Records 34 Consecutive Days of Precipitation
Rain was observed at the Tokyo city center AMeDAS station on the 29th (Tuesday). Including even light rain that was barely perceptible, the streak of consecutive days with precipitation-which began on August 27-has now reached 34 days.
This surpasses the previous record of 33 days (set between June 27 and July 29, 2019), marking the longest such streak since record-keeping began.



Reasons Behind the Prolonged Rainy Spell
So, why have rainy days persisted for so long?
The underlying cause is the presence of the autumn rain front.
Since late August, this front has frequently hovered near Honshu; the influx of warm, moist air into the front has created conditions conducive to rain across a wide area, including the Kanto region. Additionally, the repeated formation of typhoons that tracked northeastward near Kanto contributed to the continued rainfall in the area.



Outlook
In the immediate future, the autumn rain front is expected to remain stationary. Combined with the influence of warm, moist air from Typhoon No. 26, the weather will likely remain unsettled with a high probability of rain.
However, as we enter October, the stationary front is expected to dissipate. A high-pressure system from the Asian continent will likely cover much of Japan, bringing more sunny intervals to the Kanto region.
It is a relief to know that there will be more opportunities for hanging laundry outside and enjoying good weather for outings.

Weather for tomorrow, Tuesday the 29th: A stalled autumn rain front lies off the southern coast of Honshu, bringing widespread rain from eastern to western Japan.

2026/09/28 18:13

As of 3:00 PM today, Monday the 28th, Typhoon No. 26 (Surigae)-classified as "very strong"-is estimated to be moving east-northeast at a speed of 15 km/h over the waters approximately 160 km north-northeast of Minami-Daito Island.

Typhoon No. 26: Monday the 28th, 3:00 PM
==================
Intensity: Very strong
Center location: Approx. 160 km north-northeast of Minami-Daito Island
Movement: East-northeast at 15 km/h
Central pressure: 945 hPa
Max. wind speed: 45 m/s (near the center)
Max. instantaneous wind speed: 65 m/s
==================



Outlook
The typhoon is expected to continue moving east-northeast across the waters south of Japan. While its intensity is forecast to downgrade to "strong" (with a maximum wind speed of 35 m/s near the center) by tomorrow, the 29th, it is expected to pass near the Izu Islands between the 30th (Wednesday) and the 1st (Thursday) at a relatively slow pace of around 15 km/h; consequently, there is a risk of prolonged impacts in the vicinity of the Izu Islands.

Caution is advised regarding strong winds, gale-force winds, and high waves accompanied by swells in the vicinity of the Izu Islands. Conditions are expected to become particularly severe near Hachijojima, with the peak of the storm coinciding with the typhoon's closest approach tomorrow.
Please be on high alert for flying debris, fallen trees, and potential power outages; it is advisable to move any easily blown-away items indoors today.



Additionally, active rain clouds are visible near the center of the typhoon. These clouds may affect the Izu Islands-including Hachijojima and Oshima-from tomorrow, the 30th (Wed), through the 1st (Thu), necessitating caution regarding heavy rain. Evacuating after winds and rain have intensified is dangerous; please pay close attention to information from local authorities and evacuate early.

Characteristics of the Typhoon
Typhoon No. 26 is characterized as being "compact yet powerful."
While Typhoon No. 25 was large-with a strong-wind radius exceeding 500 km from its center-when it approached Honshu, Typhoon No. 26 has a strong-wind radius of only around 200 km. Infrared imagery from the Himawari weather satellite shows its size to be roughly comparable to that of Okinawa's main island.
However, the wind speed near the center is currently 45 m/s, classifying it as "very strong"; this indicates that, despite its small size, it is an exceptionally powerful typhoon.

Subsequent Path
Regarding the typhoon's subsequent path, the forecast circle is particularly large for the period between the 30th (Wed) and the 1st (Thu), indicating a high degree of uncertainty in the prediction.
The path taken on the 30th (Wed) appears to be the key factor in determining the typhoon's future movement.



According to the latest forecast, the typhoon is moving along a path slightly further north than previously predicted. While the likelihood of landfall on Honshu remains low, the probability of it approaching the Pacific coast of Honshu has increased.
Additionally, an autumn rain front is currently situated near Honshu. Warm, moist air flowing from the typhoon into this front could lead to localized heavy rainfall.
Even if the typhoon itself does not make landfall on Honshu, there is still a risk of warning-level heavy rain in the region; therefore, please continue to check for the latest updates.

Weather for tomorrow, Tuesday the 29th: A stalled autumn rain front lies off the southern coast of Honshu, bringing widespread rain from eastern to western Japan.

2026/09/28 17:56

Tomorrow, Tuesday the 29th, an autumnal rain front is expected to stall along the southern coast of Honshu. Meanwhile, a developing low-pressure system will move northward near Sakhalin.
From Eastern to Western Japan, umbrellas will likely be essential throughout the day, particularly along the Pacific coast, as the region comes under the influence of the front.



In Hokkaido, the low-pressure system will bring rain?mainly to the Sea of ??Japan side?through the morning hours. Conditions are expected to improve during the day, with sunshine returning to some areas; however, strong winds are anticipated, especially along the coast, so please exercise caution.
The Tohoku region will be under the influence of a high-pressure system, resulting in sunny skies for many areas.

Across Eastern and Western Japan, many areas will see rain due to the front.
On the Sea of ??Japan side, rain is likely, particularly in the morning. Since the rain may stop by the time you head home, please be careful not to leave your umbrella behind.
Conversely, on the Pacific coast, rain clouds will linger, leading to intermittent rainfall; please bring a large umbrella when going out.
Temperatures will remain low due to the rain, feeling more like October than late September. It will feel chilly during the day, so it is advisable to bring an outer layer or jacket when you go out.

[Tornado Advisory] Southern Chiba Prefecture: Atmospheric conditions are unstable; a tornado advisory is currently in effect.

2026/09/28 13:47

An autumn rain front extends from northern Kyushu to the southern coast of Honshu and is moving eastward. Warm, moist air is flowing toward the front, causing atmospheric instability in the southern part of Chiba Prefecture.



As of 1:30 PM, a tornado advisory has been issued for southern Chiba Prefecture; weather conditions are conducive to the formation of tornadoes and other violent gusts of wind.



If you notice signs of approaching cumulonimbus clouds?such as thunder or sudden shifts in the wind?please take steps to ensure your safety, such as moving into a sturdy building. Also, be alert for lightning, hail, and sudden heavy rain.
In the unlikely event that a tornado approaches while you are indoors, close windows and curtains, move away from windows to a windowless room, or take cover under a sturdy desk while protecting your head.
If you are outdoors, it is crucial to seek shelter behind a sturdy building to protect your head and neck. Sheds, garages, and prefabricated structures are dangerous; if no other shelter is available, lie flat in a ditch or behind a solid object.