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Monthly climate in Niihama, Japan

Last updated: July 31, 2025

Under the Köppen–Geiger climate classification Niihama features a humid subtropical climate (Cfa). Temperatures typically range between 5 °C (42 °F) and 27 °C (82 °F) through the year, but rarely can drop to -3 °C (27 °F) or can rise to as high as 33 °C (91 °F). The average annual precipitation amounts to about 1945 mm (76.6 inches) and receives 153 rainy days on the 1 mm (0.04 inches) threshold annually. Niihama enjoys an average of 3164 hours of sunshine throughout the year, and daylight varies from 9 hours 55 minutes to 14 hours 21 minutes per day.

Monthly average temperatures in Niihama, Japan

The warmest months in Niihama are July, August and September, with daily mean temperatures ranging from 24 to 27 °C (75 - 82 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from 5 to 8 °C (42 - 46 °F) throughout the day. On average each year, Niihama experiences 78 days above 25 °C (77.0 °F) and 5 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Niihama. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to June 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Maximum14°C
(58°F)		17°C
(63°F)		19°C
(66°F)		22°C
(73°F)		26°C
(80°F)		29°C
(84°F)		32°C
(91°F)		33°C
(91°F)		32°C
(90°F)		28°C
(83°F)		22°C
(73°F)		20°C
(68°F)
Mean maximum12°C
(54°F)		13°C
(56°F)		18°C
(64°F)		21°C
(70°F)		25°C
(78°F)		27°C
(81°F)		31°C
(88°F)		32°C
(90°F)		30°C
(87°F)		27°C
(80°F)		21°C
(69°F)		16°C
(61°F)
Average high8°C
(46°F)		8°C
(47°F)		13°C
(55°F)		17°C
(62°F)		21°C
(70°F)		24°C
(76°F)		28°C
(82°F)		30°C
(86°F)		26°C
(79°F)		21°C
(70°F)		16°C
(61°F)		10°C
(51°F)
Daily mean5°C
(42°F)		6°C
(43°F)		9°C
(49°F)		13°C
(57°F)		18°C
(65°F)		22°C
(71°F)		26°C
(79°F)		27°C
(82°F)		24°C
(75°F)		19°C
(66°F)		13°C
(56°F)		8°C
(46°F)
Average low3°C
(38°F)		3°C
(38°F)		6°C
(44°F)		10°C
(51°F)		15°C
(60°F)		19°C
(67°F)		24°C
(75°F)		25°C
(78°F)		22°C
(71°F)		16°C
(62°F)		10°C
(51°F)		5°C
(42°F)
Mean minimum-1°C
(31°F)		-1°C
(31°F)		2°C
(36°F)		5°C
(41°F)		10°C
(51°F)		16°C
(61°F)		21°C
(71°F)		22°C
(72°F)		17°C
(63°F)		11°C
(52°F)		5°C
(41°F)		1°C
(34°F)
Minimum-3°C
(27°F)		-2°C
(29°F)		1°C
(33°F)		3°C
(38°F)		9°C
(48°F)		15°C
(59°F)		20°C
(68°F)		20°C
(68°F)		17°C
(62°F)		10°C
(50°F)		4°C
(39°F)		0°C
(32°F)

Compare climate in Niihama with other places

Compare temperature, precipitation, sunshine, UV index in Niihama, Japan with other places around the world.

Monthly average precipitation in Niihama, Japan

Niihama usually has the most precipitation in July, September and October, with an average of 16 rainy days and 282 mm (11.1 inches) of precipitation per month. The driest months in Niihama are January, November and December. On average, 71 mm (2.8 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Niihama. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Average precipitation mm (inches)65 (2.6)85 (3.4)129 (5.1)142 (5.6)148 (5.8)199 (7.8)357 (14.1)181 (7.1)237 (9.3)253 (10.0)69 (2.7)80 (3.1)
Average precipitation days (≥ 1 mm)11111310111519131713812

Monthly sunshine hours in Niihama, Japan

The sunniest months in Niihama are May, July and August, when the sun shines an average of 9 hours 43 minutes a day. Least sunny months in Niihama: January, February and December receive an average of 7 hours 9 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Niihama. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Mean monthly sunshine hours189235272286304287287312264254241226
Mean daily daylight hours10h 9m10h 57m11h 58m13h 1m13h 54m14h 21m14h 8m13h 21m12h 21m11h 18m10h 23m9h 55m

Solar UV radiation in Niihama, Japan

Niihama experiences the highest level of ultraviolet (UV) radiation in May, July and August, when the maximum UV index can reach values of 11 - 12, which corresponds to the Extreme category of sun exposure. January, February and December are in the Moderate / High exposure category. In these months, the maximum values of the UV index do not exceed 6. For more detailed information, check out our hourly Niihama UV Index data.

Average daily maximum UV levels by month for Niihama. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2022 to January 2023.
 JanFebMarAprMayJunJulAugSepOctNovDec
UV Index (month maximum)468101111121210764