What is the hottest month in Joliet?

July — average highs around 83° with lows near 66°.

What is the coldest month in Joliet?

January, when nights typically drop to 19° and days top out near 33°.

What is the rainiest month in Joliet?

July, averaging about 5.8 in of precipitation; the driest is November at roughly 2.3 in.

How warm is Joliet over the year?

The annual mean is 52°, with about 47 in of precipitation in a typical year (1991-2020 normals).

Joliet Climate — Monthly Normals 1991-2020

Climate in Joliet

The typical year in Joliet (Illinois), from 1991-2020 normals. For what's happening now, see the current forecast; a month ahead — the 30-day outlook.

Annual mean temp

11.3°C

average across 12 months

Annual precipitation

1195 mm

yearly total

Warmest month

Jul

⌀ max 28°C

Coldest month

Jan

⌀ min -7°C

Temperatures by month

typical high (orange) · typical low (blue)

Jan

19° … 33°

Feb

21° … 38°

Mar

32° … 50°

Apr

40° … 59°

May

52° … 72°

Jun

62° … 82°

Jul

66° … 83°

Aug

65° … 82°

Sep

60° … 77°

Oct

47° … 64°

Nov

34° … 49°

Dec

27° … 41°

Precipitation by month

monthly totals across the year

Jan

65 mm

Feb

60 mm

Mar

97 mm

Apr

95 mm

May

144 mm

Jun

143 mm

Jul

148 mm

Aug

108 mm

Sep

100 mm

Oct

111 mm

Nov

59 mm

Dec

65 mm

The short version

RegionIllinois

Latitude41.5252°N

Annual mean11.3°C

Annual precipitation1195 mm

More cities · climate

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Cincinnati Ohio

Weather map — Joliet

Joliet →

Source · 1991-2020 normals

Joliet, IL Climate