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Monthly climate in Unzen, Japan

Last updated: July 31, 2025

Under the Köppen–Geiger climate classification Unzen features a humid subtropical climate (Cfa). Temperatures typically range between 8 °C (46 °F) and 29 °C (85 °F) through the year, but rarely can drop to -2 °C (29 °F) or can rise to as high as 39 °C (102 °F). The average annual precipitation amounts to about 2196 mm (86.5 inches) and receives 133 rainy days on the 1 mm (0.04 inches) threshold annually. Unzen enjoys an average of 3027 hours of sunshine throughout the year, and daylight varies from 10 hours 1 minutes to 14 hours 15 minutes per day.

Monthly average temperatures in Unzen, Japan

The warmest months in Unzen are July, August and September, with daily mean temperatures ranging from 25 to 29 °C (78 - 85 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from 8 to 10 °C (46 - 49 °F) throughout the day. On average each year, Unzen experiences 122 days above 25 °C (77.0 °F) and 3 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Unzen. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to June 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Maximum19°C
(66°F)		22°C
(71°F)		24°C
(76°F)		29°C
(84°F)		30°C
(86°F)		32°C
(90°F)		37°C
(99°F)		39°C
(102°F)		35°C
(94°F)		33°C
(91°F)		25°C
(78°F)		24°C
(76°F)
Mean maximum17°C
(63°F)		18°C
(65°F)		22°C
(72°F)		26°C
(79°F)		29°C
(84°F)		30°C
(87°F)		35°C
(94°F)		36°C
(98°F)		33°C
(92°F)		30°C
(86°F)		24°C
(75°F)		19°C
(67°F)
Average high11°C
(52°F)		12°C
(54°F)		16°C
(62°F)		21°C
(69°F)		25°C
(77°F)		27°C
(82°F)		31°C
(87°F)		33°C
(91°F)		29°C
(84°F)		25°C
(76°F)		19°C
(66°F)		13°C
(55°F)
Daily mean8°C
(46°F)		8°C
(48°F)		12°C
(55°F)		16°C
(62°F)		21°C
(69°F)		24°C
(75°F)		27°C
(82°F)		29°C
(85°F)		25°C
(78°F)		21°C
(69°F)		15°C
(59°F)		10°C
(49°F)
Average low5°C
(41°F)		5°C
(41°F)		9°C
(48°F)		12°C
(55°F)		17°C
(62°F)		21°C
(69°F)		25°C
(77°F)		26°C
(79°F)		23°C
(73°F)		17°C
(63°F)		11°C
(52°F)		6°C
(44°F)
Mean minimum-0°C
(32°F)		0°C
(33°F)		4°C
(39°F)		6°C
(43°F)		11°C
(53°F)		17°C
(63°F)		22°C
(72°F)		23°C
(74°F)		18°C
(64°F)		12°C
(53°F)		5°C
(42°F)		2°C
(35°F)
Minimum-2°C
(29°F)		-2°C
(29°F)		3°C
(37°F)		5°C
(41°F)		10°C
(50°F)		16°C
(60°F)		20°C
(68°F)		20°C
(68°F)		16°C
(62°F)		10°C
(50°F)		3°C
(38°F)		0°C
(33°F)

Compare climate in Unzen with other places

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

Monthly average precipitation in Unzen, Japan

Unzen usually has the most precipitation in June, July and August, with an average of 16 rainy days and 347 mm (13.7 inches) of precipitation per month. The driest months in Unzen are January, November and December. On average, 74 mm (2.9 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Unzen. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Average precipitation mm (inches)53 (2.1)92 (3.6)145 (5.7)135 (5.3)214 (8.4)262 (10.3)475 (18.7)303 (11.9)228 (9.0)120 (4.7)80 (3.1)89 (3.5)
Average precipitation days (≥ 1 mm)691181215191415987

Monthly sunshine hours in Unzen, Japan

The sunniest months in Unzen are April, May and August, when the sun shines an average of 9 hours 21 minutes a day. Least sunny months in Unzen: January, February and December receive an average of 6 hours 55 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Unzen. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Mean monthly sunshine hours180234263282278255266299256257236215
Mean daily daylight hours10h 14m11h 0m11h 58m12h 59m13h 50m14h 15m14h 2m13h 18m12h 20m11h 20m10h 27m10h 1m

Solar UV radiation in Unzen, Japan

Unzen experiences the highest level of ultraviolet (UV) radiation in April, 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 Unzen UV Index data.

Average daily maximum UV levels by month for Unzen. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2022 to January 2023.
 JanFebMarAprMayJunJulAugSepOctNovDec
UV Index (month maximum)468111111121211764