Kumagaya climate

Name: Kumagaya
Address: JP

Kumagaya is warmest in August, with average highs of 30 °C, and coldest in January, when nights average -1.3 °C. September is the wettest month (225 mm) and December the driest (51 mm). Figures are 1991–2020 climate normals.

Across a full year Kumagaya averages 1,619 mm of rain, 98 days above 25 °C and 57 days below freezing.

Japan · population 195,277 · 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 -1.3 °C
Driest month December 51 mm
Wettest month September 225 mm
Least cloud January 37 % cloud
Hottest on record July 40 °C
Coldest on record January -14 °C

What to expectKumagaya through the year

Kumagaya has a clear annual cycle: average daily highs run from 7.7 °C in January to 30 °C in August, a swing of 23 °C in mean temperature across the year.

Counted across a normal year, 98 days a year reach 25 °C, 33 of them reach 30 °C, 57 nights drop below freezing. The warmest reading in the 1991–2020 record is 40 °C, in July.

Rain is strongly seasonal. September averages 225 mm against 51 mm in December — 4.4 times as much. Planning around the dry months matters more here than planning around temperature.

Month by month

Month	Avg high	Rainfall	Cloud
January	7.7 °C	56 mm	37 %
February	8.8 °C	55 mm	45 %
March	12.5 °C	101 mm	54 %
April	17.8 °C	118 mm	59 %
May	22.5 °C	152 mm	68 %
June	25.2 °C	189 mm	81 %
July	28.6 °C	211 mm	78 %
August	29.9 °C	170 mm	70 %
September	26.0 °C	225 mm	70 %
October	20.4 °C	211 mm	61 %
November	15.2 °C	79 mm	47 %
December	10.2 °C	51 mm	37 %

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	7.7 °C	-1.3 °C	2.8 °C	17.4 °C	-13.7 °C	0	0	22
February	8.8 °C	-0.4 °C	3.8 °C	21.3 °C	-12.8 °C	0	0	16
March	12.5 °C	2.8 °C	7.3 °C	25.4 °C	-5.1 °C	0	0	7
April	17.8 °C	8.0 °C	12.6 °C	29.3 °C	-2.3 °C	1	0	0
May	22.5 °C	13.3 °C	17.6 °C	32.9 °C	3.9 °C	7	0	0
June	25.2 °C	17.9 °C	21.2 °C	35.0 °C	10.5 °C	16	2	0
July	28.6 °C	21.8 °C	24.8 °C	40.0 °C	15.1 °C	26	12	0
August	29.9 °C	23.0 °C	26.0 °C	37.2 °C	16.0 °C	29	16	0
September	26.0 °C	19.4 °C	22.3 °C	34.9 °C	9.7 °C	18	3	0
October	20.4 °C	13.3 °C	16.6 °C	30.4 °C	3.5 °C	2	0	0
November	15.2 °C	6.9 °C	10.7 °C	23.7 °C	-2.8 °C	0	0	0
December	10.2 °C	1.3 °C	5.4 °C	23.1 °C	-7.7 °C	0	0	11

Rain, sun and wind month by month

Month	Rainfall	Wet days	Daylight	Cloud cover	Humidity	Wind
January	56 mm	6	10.0 h/day	37 %	66 %	16 km/h
February	55 mm	7	11 h/day	45 %	65 %	17 km/h
March	101 mm	12	12 h/day	54 %	68 %	17 km/h
April	118 mm	12	13 h/day	59 %	71 %	17 km/h
May	152 mm	13	14 h/day	68 %	74 %	15 km/h
June	189 mm	17	15 h/day	81 %	80 %	13 km/h
July	211 mm	18	14 h/day	78 %	83 %	11 km/h
August	170 mm	15	14 h/day	70 %	81 %	11 km/h
September	225 mm	16	12 h/day	70 %	81 %	12 km/h
October	211 mm	13	11 h/day	61 %	78 %	12 km/h
November	79 mm	8	10 h/day	47 %	75 %	12 km/h
December	51 mm	6	9.7 h/day	37 %	69 %	14 km/h

How Kumagaya compares

The same four figures for nearby destinations, so the numbers above have something to be read against. Summer high is the warmest month's average high; winter low is the coldest month's average low.

Destination	Summer high	Winter low	Rain per year	Days above 25 °C
Kumagaya	30 °C	-1.3 °C	1,619 mm	98
Ōta · Japan	30 °C	-1.6 °C	1,478 mm	93
Isesaki · Japan	29 °C	-1.9 °C	1,476 mm	83
Kawagoe · Japan	30 °C	-2.0 °C	1,432 mm	95

Planning a trip? See the best time to visit Kumagaya.

QuestionsCommon questions about Kumagaya’s climate

When is the best time to visit Kumagaya?

That depends on what you want, so the honest answer is a comparison rather than a single month. May, June, September sit closest to 20 °C on average, August is the warmest month and December the driest. The month-by-month table above has the full picture.

How hot does Kumagaya get?

In August, the warmest month, daily highs average 30 °C. About 33 days a year pass 30 °C. The highest value in the 1991–2020 record is 40 °C.

How cold does it get in winter?

Nights average -1.3 °C in January, the coldest month. A normal year has 57 nights below freezing.

Which month is wettest in Kumagaya?

September, averaging 225 mm over 16 days with rain. The driest month is December with 51 mm. The year as a whole averages 1,619 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 Kumagaya 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
Data point: 36.135°, 139.390° (the coordinates the reanalysis values are taken for)
Dataset version: era5-1991-2020-scores1.1
Last processed: 1 August 2026

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.