Temperature records for Gunma
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Gunma, ―
Stations in Gunma
All-time records in Gunma
Records among the stations on this page (statistics as of November 1, 2026).
| Record | Station | Value | Date |
|---|---|---|---|
| Highest temperature | Isesaki | 41.8°C | Aug 5, 2025 |
| Lowest temperature | Tashiro | -17.2°C | Feb 11, 2014 |
| Heaviest daily rainfall | Nishinomaki | 471.0 mm | Oct 12, 2019 |
Range of records by station
Each bar is one station: the left dot is its record low and the right dot its record high. The statistical period differs by station, depending on when observations began or the station moved. The dates are on each station's page.
The climate of Gunma
Gunma Prefecture's heat records cluster on a single day, August 5, 2025. Isesaki observed 41.8°C, Kiryu 41.2°C, and Maebashi 41°C, each the record high for that station. Isesaki's 41.8°C is also the highest record high among all the stations covered on this site. It was a day when dry air descending over the mountains at the northern edge of the Kanto Plain piled onto the heat of the plain.
Interestingly, ordinary summers are not that extreme. On the 30-year average for 1996–2025, the August maximum is 32.5°C in Isesaki, 32.2°C in Maebashi, and 32°C in Kiryu, a difference within the prefecture of only 0.5°C. In other words, the record day exceeded a normal August by around 9°C. Evenly hot across the prefecture, breaking through only on days when conditions line up: that is the character of Gunma's summer.
Winter, in contrast, is mild. The average January maximum is in the 9°C range at all 3 stations, and the average minimum also falls within a range from -0.4°C in Maebashi to -1.8°C in Kiryu. The record low among the stations covered here is -11.8°C at Maebashi, dating back to January 3, 1923. The share of days with less than 1 mm of precipitation in January is 91.5% in Maebashi and 90.9% in Isesaki, with clear winter weather day after day, and substantial rain comes in autumn. The daily rainfall record among the stations covered here is 357.4 mm, set at Maebashi on September 15, 1947.
Record values in this description are based on data collected as of September 2026, and the normal statistics on the 30 years 1996–2025.
Monthly normals for Gunma (Maebashi)
The normals for Maebashi represent the stations in Gunma. Normals for the other stations are on each station's page.
Temperature (monthly normals)
The lines show monthly normals: the upper line is the monthly mean of the daily high and the lower line the monthly mean of the daily low, and the middle line is the monthly mean temperature. Touch the point for a month to read its values. Normals are the 1991–2020 average.
Precipitation (monthly normals, mm)
Table of monthly normals
| Month | Mean | High | Low | Precipitation |
|---|---|---|---|---|
| Jan | 3.7 | 9.1 | -0.5 | 29.7 |
| Feb | 4.5 | 10.0 | 0.0 | 26.5 |
| Mar | 7.9 | 13.5 | 3.1 | 58.3 |
| Apr | 13.4 | 19.3 | 8.2 | 74.8 |
| May | 18.6 | 24.2 | 13.6 | 99.4 |
| Jun | 22.1 | 26.8 | 18.0 | 147.8 |
| Jul | 25.8 | 30.5 | 22.0 | 202.1 |
| Aug | 26.8 | 31.7 | 23.0 | 195.6 |
| Sep | 22.9 | 27.3 | 19.3 | 204.3 |
| Oct | 17.1 | 21.7 | 13.2 | 142.2 |
| Nov | 11.2 | 16.4 | 6.9 | 43.0 |
| Dec | 6.1 | 11.5 | 1.9 | 23.8 |
Temperatures are in degrees Celsius (°C) and precipitation in mm. Blank cells have no normal.
Annual mean temperature (1996–2025)
The yearly average of the daily mean temperature (the line is broken in years with many missing values). Observing conditions at Maebashi changed on December 4, 2007; June 25, 2008; January 28, 2016 (for example, a relocation or new instruments), so the statistics may not be continuous across those dates.
The normals listed here are averages over the 30 years from 1991 to 2020. They are fixed values that stay the same until the next revision of the normals, and they show how warm or cold that month usually is in that area.