Aihara climate

Name: Aihara
Address: JP

Aihara is warmest in August, with average highs of 28 °C, and coldest in January, when nights average -1.5 °C. September is the wettest month (241 mm) and December the driest (74 mm). Figures are 1991–2020 climate normals.

Across a full year Aihara averages 1,881 mm of rain, 80 days above 25 °C and 58 days below freezing.

Japan · population 725,493 · 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 28 °C
Coldest month January -1.5 °C
Driest month December 74 mm
Wettest month September 241 mm
Least cloud January 42 % cloud
Hottest on record August 36 °C
Coldest on record February -14 °C

What to expectAihara through the year

Aihara has a clear annual cycle: average daily highs run from 7.7 °C in January to 28 °C in August, a swing of 23 °C in mean temperature across the year.

Counted across a normal year, 80 days a year reach 25 °C, 18 of them reach 30 °C, 58 nights drop below freezing. The warmest reading in the 1991–2020 record is 36 °C, in August.

Rain is strongly seasonal. September averages 241 mm against 74 mm in December — 3.3 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	83 mm	42 %
February	8.4 °C	88 mm	51 %
March	11.8 °C	151 mm	60 %
April	16.7 °C	150 mm	64 %
May	21.0 °C	162 mm	71 %
June	23.7 °C	212 mm	83 %
July	27.4 °C	206 mm	77 %
August	28.4 °C	166 mm	67 %
September	24.9 °C	241 mm	70 %
October	19.7 °C	240 mm	64 %
November	14.9 °C	107 mm	54 %
December	10.2 °C	74 mm	43 %

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	-1.5 °C	2.5 °C	17.4 °C	-13.6 °C	0	0	22
February	8.4 °C	-0.8 °C	3.4 °C	21.2 °C	-14.0 °C	0	0	17
March	11.8 °C	2.7 °C	6.9 °C	22.6 °C	-11.2 °C	0	0	7
April	16.7 °C	7.9 °C	12.1 °C	27.2 °C	-2.9 °C	0	0	1
May	21.0 °C	12.9 °C	16.8 °C	29.4 °C	3.1 °C	3	0	0
June	23.7 °C	17.2 °C	20.2 °C	32.2 °C	9.4 °C	9	1	0
July	27.4 °C	21.3 °C	24.1 °C	35.1 °C	15.0 °C	24	7	0
August	28.4 °C	22.2 °C	25.0 °C	35.9 °C	15.0 °C	28	9	0
September	24.9 °C	18.8 °C	21.6 °C	35.0 °C	8.4 °C	15	1	0
October	19.7 °C	13.1 °C	16.2 °C	29.5 °C	3.7 °C	2	0	0
November	14.9 °C	7.2 °C	10.7 °C	23.3 °C	-4.6 °C	0	0	0
December	10.2 °C	1.5 °C	5.3 °C	22.6 °C	-11.5 °C	0	0	11

Rain, sun and wind month by month

Month	Rainfall	Wet days	Daylight	Cloud cover	Humidity	Wind
January	83 mm	8	10 h/day	42 %	70 %	11 km/h
February	88 mm	10	11 h/day	51 %	70 %	12 km/h
March	151 mm	15	12 h/day	60 %	73 %	14 km/h
April	150 mm	14	13 h/day	64 %	76 %	15 km/h
May	162 mm	14	14 h/day	71 %	80 %	14 km/h
June	212 mm	17	15 h/day	83 %	86 %	12 km/h
July	206 mm	17	14 h/day	77 %	87 %	12 km/h
August	166 mm	15	14 h/day	67 %	86 %	12 km/h
September	241 mm	15	12 h/day	70 %	85 %	13 km/h
October	240 mm	14	11 h/day	64 %	82 %	12 km/h
November	107 mm	10	10 h/day	54 %	78 %	11 km/h
December	74 mm	8	9.8 h/day	43 %	73 %	11 km/h

How Aihara 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
Aihara	28 °C	-1.5 °C	1,881 mm	80
Hachiōji · Japan	29 °C	-1.9 °C	1,901 mm	85
Machida · Japan	28 °C	0.4 °C	1,619 mm	75
Atsugi · Japan	28 °C	1.8 °C	1,863 mm	74
Tokorozawa · Japan	29 °C	-2.0 °C	1,616 mm	88
Hadano · Japan	28 °C	1.2 °C	1,862 mm	82

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

QuestionsCommon questions about Aihara’s climate

When is the best time to visit Aihara?

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 Aihara get?

In August, the warmest month, daily highs average 28 °C. About 18 days a year pass 30 °C. The highest value in the 1991–2020 record is 36 °C.

How cold does it get in winter?

Nights average -1.5 °C in January, the coldest month. A normal year has 58 nights below freezing.

Which month is wettest in Aihara?

September, averaging 241 mm over 15 days with rain. The driest month is December with 74 mm. The year as a whole averages 1,881 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 Aihara 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: 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.