Kumamoto climate
Kumamoto is warmest in August, with average highs of 30 °C, and coldest in January, when nights average 3.0 °C. June is the wettest month (416 mm) and January the driest (79 mm). Figures are 1991–2020 climate normals.
Across a full year Kumamoto averages 1,953 mm of rain, 118 days above 25 °C and 7 days below freezing.
Japan · population 738,907 · 1991–2020 normals
Temperature below 0 °C to above 30 °C Rain band height is that month’s share of the wettest month
- Warmest month August 30 °C
- Coldest month January 3.0 °C
- Driest month January 79 mm
- Wettest month June 416 mm
- Least cloud October 50 % cloud
- Hottest on record August 37 °C
- Coldest on record January -6.9 °C
- Warmest sea August 27 °C
What to expectKumamoto through the year
Kumamoto has a clear annual cycle: average daily highs run from 9.0 °C in January to 30 °C in August, a swing of 21 °C in mean temperature across the year.
Counted across a normal year, 118 days a year reach 25 °C, 38 of them reach 30 °C, 7 nights drop below freezing. The warmest reading in the 1991–2020 record is 37 °C, in August.
Rain is strongly seasonal. June averages 416 mm against 79 mm in January — 5.2 times as much. Planning around the dry months matters more here than planning around temperature.
The sea off Kumamoto is warmest in August at 27 °C and coldest in February at 13 °C. Sea temperature lags the air by a month or two, which is why late summer swims warmer than early summer at the same air temperature.
Month by month
| Month | Avg high | Rainfall | Cloud |
|---|---|---|---|
| January | 9.0 °C | 79 mm | 62 % |
| February | 10.5 °C | 101 mm | 61 % |
| March | 14.0 °C | 140 mm | 62 % |
| April | 18.9 °C | 158 mm | 63 % |
| May | 23.3 °C | 174 mm | 68 % |
| June | 25.8 °C | 416 mm | 81 % |
| July | 29.1 °C | 305 mm | 71 % |
| August | 30.5 °C | 141 mm | 61 % |
| September | 27.6 °C | 167 mm | 59 % |
| October | 22.7 °C | 97 mm | 50 % |
| November | 16.9 °C | 92 mm | 52 % |
| December | 11.2 °C | 82 mm | 56 % |
Temperature month by month
| Month | Avg high | Avg low | Mean | Record high | Record low | Days above 25 °C | Days above 30 °C | Days below 0 °C |
|---|---|---|---|---|---|---|---|---|
| January | 9.0 °C | 3.0 °C | 5.9 °C | 19.5 °C | -6.9 °C | 0 | 0 | 3 |
| February | 10.5 °C | 3.6 °C | 6.9 °C | 21.2 °C | -3.3 °C | 0 | 0 | 3 |
| March | 14.0 °C | 6.5 °C | 10.1 °C | 23.8 °C | -0.8 °C | 0 | 0 | 0 |
| April | 18.9 °C | 11.0 °C | 14.7 °C | 26.8 °C | 1.0 °C | 0 | 0 | 0 |
| May | 23.3 °C | 15.5 °C | 19.2 °C | 31.3 °C | 7.7 °C | 8 | 0 | 0 |
| June | 25.8 °C | 19.7 °C | 22.5 °C | 32.2 °C | 13.5 °C | 19 | 1 | 0 |
| July | 29.1 °C | 23.4 °C | 26.0 °C | 36.6 °C | 18.1 °C | 29 | 12 | 0 |
| August | 30.5 °C | 24.0 °C | 27.0 °C | 37.3 °C | 18.2 °C | 31 | 19 | 0 |
| September | 27.6 °C | 20.8 °C | 23.9 °C | 34.6 °C | 12.4 °C | 25 | 6 | 0 |
| October | 22.7 °C | 15.2 °C | 18.6 °C | 31.1 °C | 5.1 °C | 6 | 0 | 0 |
| November | 16.9 °C | 9.9 °C | 13.2 °C | 25.1 °C | -0.3 °C | 0 | 0 | 0 |
| December | 11.2 °C | 4.9 °C | 7.9 °C | 22.1 °C | -2.6 °C | 0 | 0 | 1 |
Rain, sun and wind month by month
| Month | Rainfall | Wet days | Daylight | Cloud cover | Humidity | Wind | Sea temp |
|---|---|---|---|---|---|---|---|
| January | 79 mm | 10 | 10 h/day | 62 % | 73 % | 14 km/h | 14.4 °C |
| February | 101 mm | 10 | 11 h/day | 61 % | 72 % | 15 km/h | 13.3 °C |
| March | 140 mm | 13 | 12 h/day | 62 % | 73 % | 15 km/h | 14.1 °C |
| April | 158 mm | 12 | 13 h/day | 63 % | 74 % | 15 km/h | 16.2 °C |
| May | 174 mm | 11 | 14 h/day | 68 % | 76 % | 13 km/h | 18.9 °C |
| June | 416 mm | 17 | 14 h/day | 81 % | 83 % | 14 km/h | 22.0 °C |
| July | 305 mm | 16 | 14 h/day | 71 % | 84 % | 13 km/h | 25.4 °C |
| August | 141 mm | 14 | 13 h/day | 61 % | 80 % | 12 km/h | 27.4 °C |
| September | 167 mm | 11 | 12 h/day | 59 % | 78 % | 13 km/h | 26.2 °C |
| October | 97 mm | 8 | 11 h/day | 50 % | 75 % | 13 km/h | 23.1 °C |
| November | 92 mm | 9 | 10 h/day | 52 % | 76 % | 12 km/h | 19.7 °C |
| December | 82 mm | 10 | 10 h/day | 56 % | 74 % | 14 km/h | 16.7 °C |
Planning a trip? See the best time to visit Kumamoto.
QuestionsCommon questions about Kumamoto’s climate
When is the best time to visit Kumamoto?
That depends on what you want, so the honest answer is a comparison rather than a single month. May, June, October sit closest to 20 °C on average, August is the warmest month and January the driest. The month-by-month table above has the full picture.
How hot does Kumamoto get?
In August, the warmest month, daily highs average 30 °C. About 38 days a year pass 30 °C. The highest value in the 1991–2020 record is 37 °C.
How cold does it get in winter?
Nights average 3.0 °C in January, the coldest month. A normal year has 7 nights below freezing.
Which month is wettest in Kumamoto?
June, averaging 416 mm over 17 days with rain. The driest month is January with 79 mm. The year as a whole averages 1,953 mm.
Are these figures a forecast?
No. They are 1991–2020 climate normals: the average of thirty years, which describes what a month is usually like in Kumamoto rather than what any particular week will bring. Individual years can differ substantially from the normal.
Data sources and method
- ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
- Open-Meteo — Open-Meteo.com. CC BY 4.0
- NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
- GeoNames — GeoNames.org. CC BY 4.0
- Normal period
- 1991–2020
- Dataset version
- era5-1991-2020-scores1.1
- Last processed
Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: monthly rankings, daylight hours, beach and comfort scores. Full formulas are on the methodology page.
Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.