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Monthly climate in Oshima, Japan

Last updated: July 31, 2025

Under the Köppen–Geiger climate classification Oshima features a humid subtropical climate (Cfa). Temperatures typically range between 10 °C (50 °F) and 27 °C (80 °F) through the year, but rarely can drop to 2 °C (36 °F) or can rise to as high as 29 °C (85 °F). The average annual precipitation amounts to about 2304 mm (90.7 inches) and receives 163 rainy days on the 1 mm (0.04 inches) threshold annually. Oshima enjoys an average of 3031 hours of sunshine throughout the year, and daylight varies from 9 hours 51 minutes to 14 hours 25 minutes per day.

Monthly average temperatures in Oshima, Japan

The warmest months in Oshima are July, August and September, with daily mean temperatures ranging from 25 to 27 °C (76 - 80 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from 10 to 12 °C (50 - 55 °F) throughout the day. On average each year, Oshima experiences 62 days above 25 °C (77.0 °F) and 0 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Oshima. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to June 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Maximum18°C
(65°F)		19°C
(66°F)		19°C
(66°F)		21°C
(71°F)		23°C
(73°F)		25°C
(78°F)		29°C
(85°F)		29°C
(85°F)		29°C
(84°F)		27°C
(80°F)		23°C
(73°F)		21°C
(71°F)
Mean maximum16°C
(61°F)		17°C
(62°F)		18°C
(64°F)		20°C
(68°F)		22°C
(72°F)		24°C
(76°F)		28°C
(82°F)		29°C
(84°F)		28°C
(83°F)		26°C
(78°F)		22°C
(71°F)		19°C
(67°F)
Average high11°C
(53°F)		12°C
(54°F)		14°C
(58°F)		16°C
(62°F)		20°C
(68°F)		22°C
(73°F)		26°C
(78°F)		27°C
(81°F)		26°C
(78°F)		22°C
(72°F)		18°C
(65°F)		14°C
(58°F)
Daily mean10°C
(50°F)		10°C
(50°F)		13°C
(55°F)		15°C
(59°F)		19°C
(66°F)		22°C
(71°F)		25°C
(77°F)		27°C
(80°F)		25°C
(76°F)		21°C
(70°F)		17°C
(63°F)		12°C
(55°F)
Average low8°C
(47°F)		8°C
(47°F)		11°C
(52°F)		14°C
(57°F)		18°C
(64°F)		21°C
(70°F)		24°C
(76°F)		26°C
(79°F)		24°C
(75°F)		20°C
(68°F)		16°C
(61°F)		11°C
(52°F)
Mean minimum5°C
(40°F)		5°C
(41°F)		7°C
(44°F)		9°C
(48°F)		14°C
(58°F)		18°C
(65°F)		22°C
(71°F)		23°C
(74°F)		21°C
(69°F)		16°C
(62°F)		11°C
(51°F)		7°C
(44°F)
Minimum2°C
(36°F)		4°C
(39°F)		5°C
(42°F)		7°C
(46°F)		13°C
(56°F)		17°C
(63°F)		20°C
(69°F)		22°C
(72°F)		19°C
(67°F)		15°C
(59°F)		8°C
(47°F)		5°C
(41°F)

Compare climate in Oshima with other places

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

Monthly average precipitation in Oshima, Japan

Oshima usually has the most precipitation in June, July and October, with an average of 15 rainy days and 306 mm (12.0 inches) of precipitation per month. The driest months in Oshima are January, February and December. On average, 92 mm (3.6 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Oshima. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Average precipitation mm (inches)91 (3.6)89 (3.5)201 (7.9)157 (6.2)198 (7.8)277 (10.9)301 (11.9)155 (6.1)249 (9.8)339 (13.4)152 (6.0)95 (3.7)
Average precipitation days (≥ 1 mm)91114121114151319181512

Monthly sunshine hours in Oshima, Japan

The sunniest months in Oshima are April, May and August, when the sun shines an average of 9 hours 35 minutes a day. Least sunny months in Oshima: January, February and October receive an average of 6 hours 57 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Oshima. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Mean monthly sunshine hours189228259275293270272312254215229229
Mean daily daylight hours10h 5m10h 54m11h 58m13h 3m13h 58m14h 25m14h 12m13h 24m12h 21m11h 16m10h 20m9h 51m

Solar UV radiation in Oshima, Japan

Oshima 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 exposure category. In these months, the maximum values of the UV index do not exceed 5. For more detailed information, check out our hourly Oshima UV Index data.

Average daily maximum UV levels by month for Oshima. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2022 to January 2023.
 JanFebMarAprMayJunJulAugSepOctNovDec
UV Index (month maximum)458101111121110754