Nagaoka climate

Name: Nagaoka
Address: JP

Nagaoka is warmest in August, with average highs of 30 °C, and coldest in January, when nights average -2.7 °C. July is the wettest month (210 mm) and May the driest (96 mm). Figures are 1991–2020 climate normals.

Across a full year Nagaoka averages 1,747 mm of rain, 96 days above 25 °C and 87 days below freezing.

Japan · population 266,936 · 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 -2.7 °C
Driest month May 96 mm
Wettest month July 210 mm
Least cloud April 62 % cloud
Hottest on record August 38 °C
Coldest on record January -12 °C
Warmest sea August 27 °C

What to expectNagaoka through the year

Nagaoka has a clear annual cycle: average daily highs run from 3.5 °C in January to 30 °C in August, a swing of 25 °C in mean temperature across the year.

Counted across a normal year, 96 days a year reach 25 °C, 29 of them reach 30 °C, 87 nights drop below freezing. The warmest reading in the 1991–2020 record is 38 °C, in August.

Rain is strongly seasonal. July averages 210 mm against 96 mm in May — 2.2 times as much. Planning around the dry months matters more here than planning around temperature.

The sea off Nagaoka is warmest in August at 27 °C and coldest in March at 9.9 °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	3.5 °C	183 mm	77 %
February	4.4 °C	130 mm	74 %
March	8.6 °C	126 mm	69 %
April	15.9 °C	97 mm	62 %
May	21.7 °C	96 mm	64 %
June	25.3 °C	122 mm	73 %
July	28.2 °C	210 mm	74 %
August	29.8 °C	155 mm	62 %
September	25.6 °C	147 mm	68 %
October	19.5 °C	146 mm	64 %
November	13.2 °C	149 mm	67 %
December	6.8 °C	187 mm	74 %

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	3.5 °C	-2.7 °C	0.2 °C	14.1 °C	-12.4 °C	0	0	26
February	4.4 °C	-2.6 °C	0.6 °C	18.2 °C	-12.2 °C	0	0	24
March	8.6 °C	-0.4 °C	3.7 °C	22.1 °C	-9.4 °C	0	0	17
April	15.9 °C	5.0 °C	10.1 °C	27.3 °C	-5.1 °C	1	0	3
May	21.7 °C	10.9 °C	16.0 °C	31.8 °C	1.2 °C	6	0	0
June	25.3 °C	16.0 °C	20.4 °C	34.1 °C	7.7 °C	17	1	0
July	28.2 °C	20.4 °C	24.1 °C	37.4 °C	12.2 °C	26	9	0
August	29.8 °C	21.5 °C	25.4 °C	37.8 °C	13.0 °C	29	15	0
September	25.6 °C	17.6 °C	21.2 °C	36.0 °C	6.5 °C	16	4	0
October	19.5 °C	11.2 °C	14.9 °C	32.0 °C	0.8 °C	2	0	0
November	13.2 °C	5.3 °C	8.7 °C	24.3 °C	-5.8 °C	0	0	2
December	6.8 °C	-0.1 °C	3.0 °C	21.0 °C	-9.6 °C	0	0	16

Rain, sun and wind month by month

Month	Rainfall	Wet days	Daylight	Cloud cover	Humidity	Wind	Sea temp
January	183 mm	25	9.9 h/day	77 %	85 %	18 km/h	12.4 °C
February	130 mm	20	11 h/day	74 %	82 %	18 km/h	10.6 °C
March	126 mm	19	12 h/day	69 %	79 %	18 km/h	9.9 °C
April	97 mm	14	13 h/day	62 %	75 %	17 km/h	11.0 °C
May	96 mm	12	14 h/day	64 %	76 %	15 km/h	14.8 °C
June	122 mm	13	15 h/day	73 %	80 %	13 km/h	19.5 °C
July	210 mm	16	15 h/day	74 %	85 %	12 km/h	23.3 °C
August	155 mm	14	14 h/day	62 %	82 %	12 km/h	26.5 °C
September	147 mm	14	12 h/day	68 %	83 %	13 km/h	25.2 °C
October	146 mm	15	11 h/day	64 %	83 %	14 km/h	21.7 °C
November	149 mm	18	10 h/day	67 %	84 %	16 km/h	18.3 °C
December	187 mm	23	9.6 h/day	74 %	86 %	18 km/h	15.2 °C

How Nagaoka 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
Nagaoka	30 °C	-2.7 °C	1,747 mm	96
Niigata · Japan	28 °C	-0.09 °C	1,727 mm	70
Jōetsu · Japan	29 °C	-0.6 °C	2,259 mm	86
Nagano · Japan	28 °C	-4.4 °C	1,778 mm	77
Maebashi · Japan	29 °C	-2.0 °C	1,577 mm	83

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

QuestionsCommon questions about Nagaoka’s climate

When is the best time to visit Nagaoka?

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 May the driest. The month-by-month table above has the full picture.

How hot does Nagaoka get?

In August, the warmest month, daily highs average 30 °C. About 29 days a year pass 30 °C. The highest value in the 1991–2020 record is 38 °C.

How cold does it get in winter?

Nights average -2.7 °C in January, the coldest month. A normal year has 87 nights below freezing.

Which month is wettest in Nagaoka?

July, averaging 210 mm over 16 days with rain. The driest month is May with 96 mm. The year as a whole averages 1,747 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 Nagaoka 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: 37.450°, 138.850° (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.