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Monthly climate in Omachi, Japan

Last updated: July 31, 2025

Under the Köppen–Geiger climate classification Omachi features a humid continental climate (Dfb). Temperatures typically range between -8 °C (19 °F) and 20 °C (69 °F) through the year, but rarely can drop to -19 °C (-2 °F) or can rise to as high as 29 °C (84 °F). The average annual precipitation amounts to about 3313 mm (130.4 inches) and receives 241 rainy days on the 1 mm (0.04 inches) threshold annually. Omachi enjoys an average of 2797 hours of sunshine throughout the year, and daylight varies from 9 hours 42 minutes to 14 hours 35 minutes per day.

Monthly average temperatures in Omachi, Japan

The warmest months in Omachi are July, August and September, with daily mean temperatures ranging from 16 to 20 °C (61 - 69 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from -8 to -5 °C (19 - 24 °F) throughout the day. On average each year, Omachi experiences 18 days above 25 °C (77.0 °F) and 151 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Omachi. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to June 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Maximum4°C
(40°F)		8°C
(47°F)		13°C
(55°F)		22°C
(71°F)		24°C
(76°F)		24°C
(76°F)		28°C
(83°F)		29°C
(84°F)		27°C
(80°F)		23°C
(73°F)		16°C
(61°F)		13°C
(56°F)
Mean maximum1°C
(35°F)		4°C
(40°F)		10°C
(51°F)		16°C
(61°F)		23°C
(74°F)		22°C
(72°F)		26°C
(80°F)		28°C
(82°F)		24°C
(76°F)		21°C
(71°F)		14°C
(58°F)		6°C
(44°F)
Average high-4°C
(24°F)		-3°C
(26°F)		3°C
(37°F)		8°C
(46°F)		15°C
(60°F)		19°C
(66°F)		22°C
(73°F)		24°C
(76°F)		20°C
(68°F)		14°C
(57°F)		7°C
(45°F)		-1°C
(30°F)
Daily mean-8°C
(19°F)		-7°C
(20°F)		-1°C
(30°F)		4°C
(39°F)		11°C
(52°F)		15°C
(59°F)		19°C
(67°F)		20°C
(69°F)		16°C
(61°F)		10°C
(50°F)		3°C
(37°F)		-5°C
(24°F)
Average low-11°C
(13°F)		-10°C
(14°F)		-5°C
(24°F)		-0°C
(31°F)		6°C
(43°F)		11°C
(52°F)		16°C
(62°F)		17°C
(63°F)		13°C
(55°F)		6°C
(43°F)		-2°C
(29°F)		-8°C
(17°F)
Mean minimum-17°C
(2°F)		-16°C
(4°F)		-11°C
(12°F)		-8°C
(17°F)		-3°C
(27°F)		6°C
(43°F)		13°C
(57°F)		12°C
(55°F)		7°C
(44°F)		-1°C
(31°F)		-9°C
(17°F)		-15°C
(5°F)
Minimum-18°C
(-1°F)		-19°C
(-2°F)		-14°C
(6°F)		-11°C
(12°F)		-6°C
(21°F)		2°C
(35°F)		12°C
(54°F)		8°C
(47°F)		2°C
(36°F)		-3°C
(27°F)		-11°C
(12°F)		-16°C
(3°F)

Compare climate in Omachi with other places

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

Monthly average precipitation in Omachi, Japan

Omachi usually has the most precipitation in July, August and September, with an average of 23 rainy days and 433 mm (17.1 inches) of precipitation per month. The driest months in Omachi are January, February and November. On average, 171 mm (6.7 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Omachi. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Average precipitation mm (inches)193 (7.6)181 (7.1)198 (7.8)226 (8.9)276 (10.9)310 (12.2)565 (22.3)400 (15.8)334 (13.1)284 (11.2)139 (5.5)206 (8.1)
Average precipitation days (≥ 1 mm)211919181919252520191522

Monthly sunshine hours in Omachi, Japan

The sunniest months in Omachi are April, May and August, when the sun shines an average of 9 hours 4 minutes a day. Least sunny months in Omachi: January, February and December receive an average of 5 hours 52 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Omachi. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Mean monthly sunshine hours143209255267286267243280232211217182
Mean daily daylight hours9h 57m10h 50m11h 57m13h 7m14h 6m14h 35m14h 20m13h 29m12h 23m11h 13m10h 13m9h 42m

Solar UV radiation in Omachi, Japan

Omachi 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, November 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 Omachi UV Index data.

Average daily maximum UV levels by month for Omachi. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2022 to January 2023.
 JanFebMarAprMayJunJulAugSepOctNovDec
UV Index (month maximum)4610101111121210754