Hamamatsu climate

Name: Hamamatsu
Address: JP

Hamamatsu is warmest in August, with average highs of 30 °C, and coldest in January, when nights average 1.9 °C. July is the wettest month (269 mm) and January the driest (70 mm). Figures are 1991–2020 climate normals.

Across a full year Hamamatsu averages 2,016 mm of rain, 105 days above 25 °C and 17 days below freezing.

Japan · population 791,707 · 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 1.9 °C
Driest month January 70 mm
Wettest month July 269 mm
Least cloud December 35 % cloud
Hottest on record August 40 °C
Coldest on record January -3.8 °C
Warmest sea August 27 °C

What to expectHamamatsu through the year

Hamamatsu has a clear annual cycle: average daily highs run from 9.5 °C in January to 30 °C in August, a swing of 22 °C in mean temperature across the year.

Counted across a normal year, 105 days a year reach 25 °C, 28 of them reach 30 °C, 17 nights drop below freezing. The warmest reading in the 1991–2020 record is 40 °C, in August.

Rain is strongly seasonal. July averages 269 mm against 70 mm in January — 3.8 times as much. Planning around the dry months matters more here than planning around temperature.

The sea off Hamamatsu is warmest in August at 27 °C and coldest in February at 16 °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	9.5 °C	70 mm	36 %
February	10.6 °C	94 mm	43 %
March	13.8 °C	148 mm	51 %
April	18.3 °C	166 mm	57 %
May	22.3 °C	187 mm	66 %
June	25.0 °C	269 mm	79 %
July	28.7 °C	269 mm	73 %
August	30.1 °C	156 mm	60 %
September	27.1 °C	255 mm	62 %
October	22.1 °C	213 mm	56 %
November	17.0 °C	120 mm	46 %
December	11.8 °C	71 mm	35 %

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	9.5 °C	1.9 °C	5.2 °C	17.4 °C	-3.8 °C	0	0	7
February	10.6 °C	2.3 °C	6.0 °C	20.2 °C	-3.5 °C	0	0	7
March	13.8 °C	5.1 °C	9.1 °C	22.0 °C	-1.5 °C	0	0	1
April	18.3 °C	9.8 °C	13.9 °C	26.8 °C	0.8 °C	0	0	0
May	22.3 °C	14.4 °C	18.2 °C	32.2 °C	5.3 °C	4	0	0
June	25.0 °C	18.9 °C	21.8 °C	33.3 °C	12.7 °C	14	1	0
July	28.7 °C	23.0 °C	25.6 °C	35.9 °C	17.3 °C	29	9	0
August	30.1 °C	24.1 °C	26.8 °C	39.6 °C	17.9 °C	30	15	0
September	27.1 °C	21.0 °C	23.7 °C	35.8 °C	12.1 °C	24	4	0
October	22.1 °C	15.4 °C	18.4 °C	31.2 °C	6.8 °C	4	0	0
November	17.0 °C	9.6 °C	13.0 °C	26.2 °C	1.8 °C	0	0	0
December	11.8 °C	4.2 °C	7.6 °C	22.2 °C	-3.6 °C	0	0	2

Rain, sun and wind month by month

Month	Rainfall	Wet days	Daylight	Cloud cover	Humidity	Wind	Sea temp
January	70 mm	6	10 h/day	36 %	65 %	25 km/h	16.3 °C
February	94 mm	8	11 h/day	43 %	64 %	24 km/h	15.6 °C
March	148 mm	11	12 h/day	51 %	68 %	24 km/h	15.8 °C
April	166 mm	11	13 h/day	57 %	71 %	23 km/h	17.3 °C
May	187 mm	12	14 h/day	66 %	76 %	20 km/h	19.3 °C
June	269 mm	15	14 h/day	79 %	82 %	19 km/h	21.9 °C
July	269 mm	16	14 h/day	73 %	84 %	18 km/h	24.8 °C
August	156 mm	16	13 h/day	60 %	81 %	18 km/h	26.7 °C
September	255 mm	16	12 h/day	62 %	80 %	18 km/h	25.7 °C
October	213 mm	12	11 h/day	56 %	77 %	18 km/h	23.4 °C
November	120 mm	9	10 h/day	46 %	73 %	19 km/h	21.0 °C
December	71 mm	6	9.8 h/day	35 %	69 %	23 km/h	18.6 °C

How Hamamatsu 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
Hamamatsu	30 °C	1.9 °C	2,016 mm	105
Toyohashi · Japan	30 °C	1.6 °C	1,881 mm	106
Nishio · Japan	30 °C	1.4 °C	1,497 mm	102
Anjō · Japan	31 °C	-0.08 °C	1,493 mm	111
Shizuoka · Japan	29 °C	2.6 °C	2,441 mm	89
Toyota · Japan	31 °C	0.03 °C	1,878 mm	115

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

QuestionsCommon questions about Hamamatsu’s climate

When is the best time to visit Hamamatsu?

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 Hamamatsu get?

In August, the warmest month, daily highs average 30 °C. About 28 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 1.9 °C in January, the coldest month. A normal year has 17 nights below freezing.

Which month is wettest in Hamamatsu?

July, averaging 269 mm over 16 days with rain. The driest month is January with 70 mm. The year as a whole averages 2,016 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 Hamamatsu 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: 34.700°, 137.733° (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.