Joliet, IL Weather by Month and Climate Averages

How much rain does Joliet get?

Joliet gets 38.0 in of precipitation in an average year, spread over about 122 days with measurable rain. That is more rainy days than 79% of the US.

July is the wettest month, with 4.5 in. February is the driest, with 1.8 in. May has the most rainy days, about 12.

The longest dry spell in the last five years lasted 25 days, to September 22, 2024.

See where Joliet ranks: rainiest cities in the US, US cities with the most rainy days, rainiest cities in Illinois.

Does it snow in Joliet?

Yes. Joliet gets about 16.9 in of snow in an average season, measured at the reporting station.

The snowiest winter on record is 2013–14, with 55.7 in.

The most recent measurable snow at the station fell on March 24, 2006.

See where Joliet ranks: snowiest cities in the US.

Joliet weather by month

Joliet weather in January

In January, Joliet averages a high of 32°F and a low of 17°F. It gets 2.0 in of precipitation over about 11 rainy days. The sun is out about 24% of daylight hours. The January record high is 65°F (1997) and the record low is -26°F (1985).

Joliet weather in February

In February, Joliet averages a high of 36°F and a low of 20°F. It gets 1.8 in of precipitation over about 9 rainy days. The sun is out about 42% of daylight hours. The February record high is 73°F (2000) and the record low is -20°F (1979).

Joliet weather in March

In March, Joliet averages a high of 47°F and a low of 29°F. It gets 2.3 in of precipitation over about 10 rainy days. The sun is out about 34% of daylight hours. The March record high is 86°F (1986) and the record low is -7°F (2002).

Joliet weather in April

In April, Joliet averages a high of 60°F and a low of 39°F. It gets 3.9 in of precipitation over about 12 rainy days. The sun is out about 38% of daylight hours. The April record high is 92°F (1986) and the record low is 11°F (1982).

Joliet weather in May

In May, Joliet averages a high of 71°F and a low of 49°F. It gets 4.5 in of precipitation over about 12 rainy days. The sun is out about 38% of daylight hours. The May record high is 95°F (2012) and the record low is 28°F (2020). May is one of the most comfortable months to visit.

Joliet weather in June

In June, Joliet averages a high of 81°F and a low of 60°F. It gets 4.3 in of precipitation over about 11 rainy days. The sun is out about 50% of daylight hours. The June record high is 104°F (1988) and the record low is 35°F (1985).

Joliet weather in July

In July, Joliet averages a high of 84°F and a low of 64°F. It gets 4.5 in of precipitation over about 9 rainy days. The sun is out about 48% of daylight hours. The July record high is 103°F (1995) and the record low is 47°F (2024).

Joliet weather in August

In August, Joliet averages a high of 82°F and a low of 63°F. It gets 4.0 in of precipitation over about 9 rainy days. The sun is out about 52% of daylight hours. The August record high is 102°F (1988) and the record low is 39°F (1986).

Joliet weather in September

In September, Joliet averages a high of 77°F and a low of 55°F. It gets 3.2 in of precipitation over about 8 rainy days. The sun is out about 53% of daylight hours. The September record high is 97°F (1978) and the record low is 32°F (1983). September is one of the most comfortable months to visit.

Joliet weather in October

In October, Joliet averages a high of 63°F and a low of 43°F. It gets 3.1 in of precipitation over about 9 rainy days. The sun is out about 50% of daylight hours. The October record high is 88°F (2025) and the record low is 17°F (1976). October is one of the most comfortable months to visit.

Joliet weather in November

In November, Joliet averages a high of 49°F and a low of 32°F. It gets 2.5 in of precipitation over about 10 rainy days. The sun is out about 45% of daylight hours. The November record high is 78°F (1978) and the record low is -2°F (1977).

Joliet weather in December

In December, Joliet averages a high of 37°F and a low of 22°F. It gets 1.9 in of precipitation over about 10 rainy days. The sun is out about 31% of daylight hours. The December record high is 70°F (1982) and the record low is -20°F (1983).

Sunshine, humidity and wind in Joliet

September is the sunniest month in Joliet, with sunshine about 53% of daylight hours. January is the cloudiest, at 24%. Over the year the sun shines about 42% of daylight hours. Joliet is cloudier than 80% of the US.

Humidity peaks in January at 77% and is lowest in June at 59%.

Joliet has about 16 days a year above 90°F. Joliet is cooler than 67% of the US.

Thunderstorms occur on about 3 days a year.

See where Joliet ranks: sunniest cities in the US, cloudiest cities in the US, hottest cities in the US.

First and last freeze in Joliet

The first fall freeze in Joliet typically comes around October 19, and the last spring freeze around April 21. That leaves a frost-free growing season of about 181 days.

Joliet weather records

The hottest temperature on record at the Joliet station is 104°F, on June 26, 1988. The coldest is -26°F, on January 20, 1985.

The wettest day on record brought 13.6 in of rain, on July 18, 1996.

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

The annual mean temperature has changed by +0.5°F per decade since 1976.

The best time to visit Joliet

The most comfortable time to visit is typically May and September to October, when daytime highs sit near 70°F.

Winter (December–February) is cold, with average highs around 35°F and lows near 19°F. Snow is possible.

Spring (March–May) is mild, with average highs around 60°F and lows near 39°F.

Summer (June–August) is hot, with average highs around 82°F and lows near 62°F.

Autumn (September–November) is mild, with average highs around 63°F and lows near 44°F.

Joliet climate questions

How much rain does Joliet get?

Joliet gets 38.0 in of precipitation in an average year, over about 122 rainy days.

What is the wettest month in Joliet?

July is the wettest month in Joliet, with 4.5 in. February is the driest, with 1.8 in.

How many rainy days does Joliet have a year?

Joliet has about 122 days with measurable rain in an average year. May has the most, about 12.

Does it snow in Joliet?

Yes. Joliet gets about 16.9 in of snow in an average season. The snowiest winter on record is 2013–14, with 55.7 in.

What is the hottest month in Joliet?

July is the warmest month in Joliet, with an average high of 84°F.

What is the coldest month in Joliet?

January is the coldest month in Joliet, with an average low of 17°F.

What is the record high temperature in Joliet?

The record high at the Joliet station is 104°F, set on June 26, 1988. The record low is -26°F, on January 20, 1985.

What is the sunniest month in Joliet?

September is the sunniest month in Joliet, with sunshine about 53% of daylight hours. January is the cloudiest.

When is the first frost in Joliet?

The first fall freeze in Joliet typically comes around October 19. The last spring freeze is around April 21.

What is the best time to visit Joliet?

The most comfortable time to visit is typically May and September to October, when daytime highs sit near 70°F.