Iiyama Weather & Climate: Best Time to Visit
Average temperatures, rainfall, sunshine and the best time to visit Iiyama.
Climate overview of Iiyama
Iiyama, Nagano Prefecture, Japan, sees big temperature differences between seasons, with August peaking at 29°C (84°F) and January dropping to 3°C (37°F).
Rain/snowfall is high, totalling around 2163 mm (85 in) per year. July is the wettest month and April the driest. The city also experiences two distinct rainy seasons, December to February and June to October, with warm summers and cold winters. May is the sunniest month, averaging 6.6 hours of sunshine per day.
Iiyama Weather by Month
Pick a month to see the average temperature, rainfall and sunshine in Iiyama - and find the best time to visit.
Monthly Temperature in Iiyama
Visitors to Iiyama can expect significant temperature changes throughout the year. Average maximum daytime temperatures range from a comfortable 29°C (84°F) in August, the warmest time of the year, to a chilly 3°C (37°F) during cooler months like January.
At night, you can expect temperatures ranging from 20°C (68°F) in August to around -5°C (23°F) during January.
Check out our detailed temperature page for more information.
Temperature ranges by month
Rainfall in Iiyama
Iiyama is known for its substantial rain/snowfall, with annual precipitation reaching 2163 mm (85 in). While rainfall varies throughout the year, each season offers its own charm. July brings wetter days averaging 257 mm (10 in) of precipitation, spread over 21 rainy days.
In contrast, the driest month April experiences a drier climate, with about 126 mm (5 in) of rainfall spread across 17 rainy days. For more details, please visit our Iiyama Precipitation page.
The mean monthly precipitation over the year, including rain, hail, and snow
The average number of days each month with precipitation
Sunshine Hours in Iiyama
Seasonal changes in sunshine hours are quite dramatic in Iiyama. While May receives considerable daily sunshine with up to 6.6 hours, January marks the darkest time of the year, where sunshine is scarce with only 2.2 hours of sunlight per day.
Visit our detailed sunshine hours page for more information.
Monthly hours of sunshine
Daily hours of sunshine
Humidity in Iiyama by Month
The relative humidity is high throughout the year in Iiyama.
The city experiences its highest humidity in July, reaching 80%. In April, the humidity drops to its lowest level at 67%. What does this mean? Read our detailed page on humidity levels for further details.
Relative humidity over the year
Best Time to Visit Iiyama
Monthly ratings reflect general weather comfort, based on daytime temperature and rainfall. Swimming and winter conditions are highlighted separately where relevant.
- Best overall: May
- Warmest weather: July and August
- Most sunshine: May and August
- Seasonal pattern: Two distinct rainy seasons, December to February and June to October, with warm summers and cold winters
- Coldest conditions: January, with freezing nights around -5°C (23°F).
Frequently asked questions about the climate in Iiyama
What is the best time to visit Iiyama?
May typically offers the most optimal weather in Iiyama. In contrast, January, February, March, November and December tend to have less optimal conditions. Iiyama has two distinct rainy seasons, December to February and June to October, with warm summers and cold winters.
What temperatures can I expect in Iiyama?
Daytime highs range from 3°C (37°F) in January to 29°C (84°F) in August. Nighttime lows range from -5°C (23°F) to 20°C (68°F). Temperatures vary considerably through the year.
How much rain does Iiyama get?
Annual rainfall is around 2163 mm (85 in). July is the wettest month with 257 mm (10 in), while April is the driest with 126 mm (5 in).
How sunny is Iiyama?
Iiyama receives around 1,602 hours of sunshine per year. May is the sunniest month with 198 hours, while January is the cloudiest with just 67 hours.
Iiyama 3-Day Forecast
Iiyama 3-Day Forecast
Iiyama on the map
Iiyama is highlighted - select any city to see its climate.
Popular this month
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