Monthly climate in Iwanai, Hokkaido, Japan

Last updated: May 6, 2024

Under the Köppen–Geiger climate classification Iwanai features a humid continental climate (Dfb).Temperatures typically range between -4 °C (25 °F) and 21 °C (70 °F) through the year, but rarely can drop to -14 °C (7 °F) or can rise to as high as 31 °C (88 °F).The average annual precipitation amounts to about 1431 mm (56.4 inches) and receives 202 rainy days on the 1 mm (0.04 inches) threshold annually.Iwanai enjoys an average of 2948 hours of sunshine throughout the year, and daylight varies from 9 hours 3 minutes to 15 hours 17 minutes per day.

Monthly average temperatures in Iwanai, Hokkaido, Japan §

The warmest months in Iwanai are July, August and September, with daily mean temperatures ranging from 18 to 21 °C (64 - 70 °F) throughout the day. The coldest temperatures usually occur in January, February and December, when daily mean temperatures range from -4 to -2 °C (25 - 29 °F) throughout the day. On average each year, Iwanai experiences 14 days above 25 °C (77.0 °F) and 115 days below 0 °C (32.0 °F).

Monthly average temperatures with daily means, minimums and maximums for period, average high and low temperatures in Iwanai, Hokkaido, Japan.Generated using Copernicus Climate Change Service information.Data for period from January 2017 to June 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Maximum 4°C
(40°F)
7°C
(44°F)
13°C
(55°F)
17°C
(63°F)
26°C
(79°F)
25°C
(77°F)
30°C
(86°F)
31°C
(88°F)
28°C
(82°F)
22°C
(72°F)
15°C
(60°F)
11°C
(52°F)
Mean maximum 3°C
(37°F)
5°C
(41°F)
9°C
(49°F)
15°C
(60°F)
22°C
(71°F)
21°C
(70°F)
27°C
(82°F)
28°C
(83°F)
25°C
(78°F)
20°C
(69°F)
15°C
(59°F)
8°C
(46°F)
Average high -2°C
(29°F)
-1°C
(30°F)
3°C
(38°F)
8°C
(47°F)
15°C
(59°F)
18°C
(64°F)
23°C
(73°F)
24°C
(75°F)
21°C
(69°F)
15°C
(59°F)
7°C
(45°F)
-0°C
(32°F)
Daily mean -4°C
(25°F)
-3°C
(26°F)
1°C
(34°F)
5°C
(41°F)
11°C
(53°F)
15°C
(59°F)
20°C
(68°F)
21°C
(70°F)
18°C
(64°F)
12°C
(53°F)
5°C
(41°F)
-2°C
(29°F)
Average low -6°C
(21°F)
-5°C
(22°F)
-2°C
(29°F)
2°C
(36°F)
8°C
(47°F)
12°C
(54°F)
17°C
(64°F)
18°C
(65°F)
15°C
(59°F)
9°C
(48°F)
3°C
(37°F)
-4°C
(25°F)
Mean minimum -12°C
(11°F)
-11°C
(13°F)
-6°C
(21°F)
-2°C
(28°F)
4°C
(40°F)
8°C
(46°F)
14°C
(57°F)
14°C
(57°F)
10°C
(51°F)
4°C
(39°F)
-3°C
(26°F)
-9°C
(16°F)
Minimum -14°C
(7°F)
-13°C
(8°F)
-8°C
(18°F)
-4°C
(25°F)
3°C
(38°F)
6°C
(42°F)
10°C
(51°F)
12°C
(55°F)
8°C
(47°F)
3°C
(37°F)
-6°C
(21°F)
-12°C
(11°F)

Compare climate in Iwanai with other places

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

Monthly average precipitation in Iwanai, Hokkaido, Japan §

Iwanai usually has the most precipitation in October, November and December, with an average of 22 rainy days and 162 mm (6.4 inches) of precipitation per month.The driest months in Iwanai are April, May and July. On average, 89 mm (3.5 inches) of precipitation falls during these months.

Monthly average precipitation and precipitation days in Iwanai, Hokkaido, Japan.Generated using Copernicus Climate Change Service information.Data for period from January 2017 to January 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Average precipitation mm (inches) 99 (3.9) 103 (4.1) 98 (3.8) 88 (3.4) 86 (3.4) 109 (4.3) 94 (3.7) 145 (5.7) 126 (5.0) 149 (5.9) 176 (6.9) 159 (6.3)
Average precipitation days (≥ 1 mm) 20 22 16 12 12 11 11 15 15 17 24 27

Monthly sunshine hours in Iwanai, Hokkaido, Japan §

The sunniest months in Iwanai are May, July and August, when the sun shines an average of 10 hours 2 minutes a day.Least sunny months in Iwanai: January, November and December receive an average of 5 hours 9 minutes of sunshine daily.

Mean monthly sunshine duration, average sunshine hours per day and mean daily daylight hours in Iwanai, Hokkaido, Japan.Generated using Copernicus Atmosphere Monitoring Service information.Data for period from January 2017 to January 2022.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Mean monthly sunshine hours 128 188 246 292 313 295 321 299 277 238 181 164
Mean daily daylight hours 9h 23m 10h 30m 11h 56m 13h 24m 14h 38m 15h 17m 14h 57m 13h 52m 12h 27m 11h 0m 9h 43m 9h 3m

Solar UV radiation in Iwanai, Hokkaido, Japan §

Iwanai experiences the highest level of ultraviolet (UV) radiation in May, July and August, when the maximum UV index can reach values of 9 - 10, which corresponds to the Very High category of sun exposure.January, February and December are in the Low / Moderate exposure category. In these months, the maximum values of the UV index do not exceed 3. For more detailed information, check out our hourly Iwanai UV Index data.

Average daily maximum UV levels by month for Iwanai, Hokkaido, Japan.Generated using Copernicus Atmosphere Monitoring Service information.Data for period from January 2022 to January 2023.
  Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
UV Index (month maximum) 2 3 5 7 9 9 9 10 8 5 3 2