Iwanai Weather & Climate: Best Time to Visit

The climate in Iwanai is known for significant temperature differences throughout the year, making the weather dynamic. Average daytime temperatures reach a comfortable 25°C (77°F) in August. In January, the coolest month of the year, temperatures drop to a very cold -1°C (30°F).

At night, temperatures range from around 18°C (64°F) in August to -7°C (19°F) in January.

Check out our detailed temperature page for more information.

Temperature ranges by month

Iwanai has a notably wet climate with abundant precipitation, recording 1416 mm (56 in) of rain/snowfall per year. Iwanai can be quite wet during August, receiving approximately 171 mm (6.7 in) of precipitation over 18 rainy days.

In contrast, during the driest month (April), you will experience much drier conditions, with 78 mm (3.1 in) of precipitation spread across 18 rainy days days. For more details, please visit our Iwanai Precipitation page.

The mean monthly precipitation over the year, including rain, hail, and snow

The average number of days each month with precipitation

Iwanai can be enjoyed more throughout the sunniest month of May under a blue sky, with approximately 6.6 hours of sunshine daily. In contrast, the city experiences much darker days in December, with only 2.9 hours of sunlight per day.

Visit our detailed sunshine hours page for more information.

Monthly hours of sunshine

Daily hours of sunshine

The relative humidity is high throughout the year in Iwanai.

The city experiences its highest humidity in July, reaching 76%. In April, the humidity drops to its lowest level at 62%. What does this mean? Read our detailed page on humidity levels for further details.

Relative humidity over the year