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Monthly climate in Isawa, Japan

Last updated: July 31, 2025

Under the Köppen–Geiger climate classification Isawa features a humid continental climate (Dfb). Temperatures typically range between -1 °C (31 °F) and 23 °C (73 °F) through the year, but rarely can drop to -17 °C (2 °F) or can rise to as high as 33 °C (91 °F). The average annual precipitation amounts to about 1864 mm (73.4 inches) and receives 183 rainy days on the 1 mm (0.04 inches) threshold annually. Isawa enjoys an average of 2877 hours of sunshine throughout the year, and daylight varies from 9 hours 46 minutes to 14 hours 31 minutes per day.

Monthly average temperatures in Isawa, Japan

The warmest months in Isawa are July, August and September, with daily mean temperatures ranging from 18 to 23 °C (65 - 73 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from -1 to 2 °C (31 - 36 °F) throughout the day. On average each year, Isawa experiences 43 days above 25 °C (77.0 °F) and 101 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Isawa. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to June 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Maximum11°C
(52°F)		17°C
(63°F)		21°C
(70°F)		25°C
(78°F)		28°C
(82°F)		28°C
(82°F)		32°C
(90°F)		33°C
(91°F)		31°C
(87°F)		27°C
(80°F)		19°C
(66°F)		18°C
(65°F)
Mean maximum9°C
(49°F)		13°C
(56°F)		18°C
(65°F)		22°C
(72°F)		27°C
(80°F)		25°C
(78°F)		30°C
(86°F)		31°C
(88°F)		28°C
(83°F)		25°C
(77°F)		18°C
(64°F)		13°C
(55°F)
Average high4°C
(39°F)		5°C
(42°F)		10°C
(50°F)		14°C
(58°F)		19°C
(67°F)		22°C
(71°F)		25°C
(77°F)		27°C
(80°F)		22°C
(72°F)		17°C
(63°F)		12°C
(55°F)		7°C
(44°F)
Daily mean-1°C
(31°F)		0°C
(33°F)		5°C
(41°F)		9°C
(48°F)		14°C
(58°F)		17°C
(63°F)		21°C
(70°F)		23°C
(73°F)		18°C
(65°F)		13°C
(55°F)		7°C
(45°F)		2°C
(36°F)
Average low-4°C
(24°F)		-4°C
(25°F)		-0°C
(32°F)		4°C
(39°F)		10°C
(49°F)		14°C
(57°F)		18°C
(65°F)		19°C
(67°F)		15°C
(60°F)		10°C
(49°F)		3°C
(37°F)		-2°C
(29°F)
Mean minimum-10°C
(14°F)		-10°C
(15°F)		-5°C
(23°F)		-3°C
(28°F)		2°C
(36°F)		10°C
(49°F)		15°C
(59°F)		16°C
(60°F)		10°C
(51°F)		3°C
(38°F)		-2°C
(28°F)		-7°C
(20°F)
Minimum-17°C
(2°F)		-12°C
(11°F)		-7°C
(21°F)		-4°C
(25°F)		0°C
(33°F)		7°C
(44°F)		13°C
(56°F)		12°C
(55°F)		9°C
(49°F)		2°C
(35°F)		-4°C
(26°F)		-8°C
(17°F)

Compare climate in Isawa with other places

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

Monthly average precipitation in Isawa, Japan

Isawa usually has the most precipitation in July, September and October, with an average of 21 rainy days and 284 mm (11.2 inches) of precipitation per month. The driest months in Isawa are January, November and December. On average, 52 mm (2.0 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Isawa. Generated using Copernicus Climate Change Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Average precipitation mm (inches)48 (1.9)58 (2.3)144 (5.7)138 (5.4)148 (5.8)179 (7.1)320 (12.6)190 (7.5)208 (8.2)324 (12.8)56 (2.2)52 (2.1)
Average precipitation days (≥ 1 mm)691315151924232219108

Monthly sunshine hours in Isawa, Japan

The sunniest months in Isawa are April, May and August, when the sun shines an average of 9 hours 0 minutes a day. Least sunny months in Isawa: January, July and October receive an average of 6 hours 36 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Isawa. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2017 to January 2022.
 JanFebMarAprMayJunJulAugSepOctNovDec
Mean monthly sunshine hours191232258270282255219275228203227232
Mean daily daylight hours10h 1m10h 52m11h 58m13h 5m14h 2m14h 31m14h 16m13h 27m12h 22m11h 15m10h 16m9h 46m

Solar UV radiation in Isawa, Japan

Isawa 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 Isawa UV Index data.

Average daily maximum UV levels by month for Isawa. Generated using Copernicus Atmosphere Monitoring Service information. Data for period from January 2022 to January 2023.
 JanFebMarAprMayJunJulAugSepOctNovDec
UV Index (month maximum)468101111121110754