Iruma, Saitama Weather by Month and Climate Averages

How much rain does Iruma get?

Iruma gets 1127 mm of precipitation in an average year, spread over about 82 days with measurable rain. That is fewer rainy days than 97% of Japan.

September is the wettest month, with 191 mm. February is the driest, with 27 mm. July has the most rainy days, about 11.

The longest dry spell in the last five years lasted 27 days, to January 12, 2024.

Iruma weather by month

Iruma weather in January

In January, Iruma averages a high of 9°C and a low of -4°C. It gets 35 mm of precipitation over about 3 rainy days. The sun is out about 59% of daylight hours. The January record high is 19°C (1996) and the record low is -12°C (1970).

Iruma weather in February

In February, Iruma averages a high of 10°C and a low of -4°C. It gets 27 mm of precipitation over about 4 rainy days. The sun is out about 56% of daylight hours. The February record high is 26°C (2009) and the record low is -12°C (1984).

Iruma weather in March

In March, Iruma averages a high of 13°C and a low of 0°C. It gets 56 mm of precipitation over about 6 rainy days. The sun is out about 42% of daylight hours. The March record high is 27°C (2020) and the record low is -11°C (1977).

Iruma weather in April

In April, Iruma averages a high of 19°C and a low of 6°C. It gets 69 mm of precipitation over about 6 rainy days. The sun is out about 38% of daylight hours. The April record high is 33°C (2004) and the record low is -4°C (1978). April is one of the most comfortable months to visit.

Iruma weather in May

In May, Iruma averages a high of 24°C and a low of 11°C. It gets 86 mm of precipitation over about 8 rainy days. The sun is out about 28% of daylight hours. The May record high is 37°C (1993) and the record low is 1°C (1972). May is one of the most comfortable months to visit.

Iruma weather in June

In June, Iruma averages a high of 26°C and a low of 16°C. It gets 122 mm of precipitation over about 10 rainy days. The sun is out about 19% of daylight hours. The June record high is 38°C (2011) and the record low is 6°C (1978). June is one of the most comfortable months to visit.

Iruma weather in July

In July, Iruma averages a high of 30°C and a low of 21°C. It gets 152 mm of precipitation over about 11 rainy days. The sun is out about 23% of daylight hours. The July record high is 39°C (2018) and the record low is 9°C (1976).

Iruma weather in August

In August, Iruma averages a high of 31°C and a low of 21°C. It gets 141 mm of precipitation over about 8 rainy days. The sun is out about 33% of daylight hours. The August record high is 39°C (1994) and the record low is 13°C (1976).

Iruma weather in September

In September, Iruma averages a high of 27°C and a low of 17°C. It gets 191 mm of precipitation over about 10 rainy days. The sun is out about 26% of daylight hours. The September record high is 38°C (1984) and the record low is 7°C (1992).

Iruma weather in October

In October, Iruma averages a high of 21°C and a low of 11°C. It gets 175 mm of precipitation over about 8 rainy days. The sun is out about 38% of daylight hours. The October record high is 32°C (2018) and the record low is 0°C (1971). October is one of the most comfortable months to visit.

Iruma weather in November

In November, Iruma averages a high of 16°C and a low of 3°C. It gets 43 mm of precipitation over about 5 rainy days. The sun is out about 54% of daylight hours. The November record high is 26°C (2023) and the record low is -6°C (1973).

Iruma weather in December

In December, Iruma averages a high of 11°C and a low of -2°C. It gets 30 mm of precipitation over about 3 rainy days. The sun is out about 66% of daylight hours. The December record high is 25°C (2004) and the record low is -12°C (1976).

Sunshine, humidity and wind in Iruma

December is the sunniest month in Iruma, with sunshine about 66% of daylight hours. June is the cloudiest, at 19%. Over the year the sun shines about 40% of daylight hours. Iruma is sunnier than 65% of Japan.

Humidity peaks in September at 83% and is lowest in February at 59%.

Iruma has about 29 days a year above 32°C. Iruma is hotter than 75% of Japan.

First and last freeze in Iruma

The first fall freeze in Iruma typically comes around November 16, and the last spring freeze around April 6. That leaves a frost-free growing season of about 224 days.

Iruma weather records

The hottest temperature on record at the Iruma station is 39°C, on August 7, 1994. The coldest is -12°C, on January 17, 1970.

The wettest day on record brought 294 mm of rain, on September 12, 1982.

32 all-time records have been set at the station since 1970.

The best time to visit Iruma

The most comfortable time to visit is typically April to June and October, when daytime highs sit near 23°C.

Winter (December–February) is chilly, with average highs around 10°C and lows near -4°C.

Spring (March–May) is mild, with average highs around 19°C and lows near 5°C.

Summer (June–August) is hot, with average highs around 29°C and lows near 19°C. It can feel humid.

Autumn (September–November) is warm, with average highs around 21°C and lows near 10°C.

Iruma climate questions

How much rain does Iruma get?

Iruma gets 1127 mm of precipitation in an average year, over about 82 rainy days.

What is the wettest month in Iruma?

September is the wettest month in Iruma, with 191 mm. February is the driest, with 27 mm.

How many rainy days does Iruma have a year?

Iruma has about 82 days with measurable rain in an average year. July has the most, about 11.

What is the hottest month in Iruma?

August is the warmest month in Iruma, with an average high of 31°C.

What is the coldest month in Iruma?

January is the coldest month in Iruma, with an average low of -4°C.

What is the record high temperature in Iruma?

The record high at the Iruma station is 39°C, set on August 7, 1994. The record low is -12°C, on January 17, 1970.

What is the sunniest month in Iruma?

December is the sunniest month in Iruma, with sunshine about 66% of daylight hours. June is the cloudiest.

When is the first frost in Iruma?

The first fall freeze in Iruma typically comes around November 16. The last spring freeze is around April 6.

What is the best time to visit Iruma?

The most comfortable time to visit is typically April to June and October, when daytime highs sit near 23°C.