What is the hottest month in Naperville?

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

What is the coldest month in Naperville?

January, when nights typically drop to 18° and days top out near 32°.

What is the rainiest month in Naperville?

July, averaging about 5.5 in of precipitation; the driest is November at roughly 2.2 in.

How warm is Naperville over the year?

The annual mean is 52°, with about 45 in of precipitation in a typical year (1991-2020 normals).

Naperville Climate — Monthly Normals 1991-2020

Climate in Naperville

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

Annual mean temp

10.9°C

average across 12 months

Annual precipitation

1151 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

-8° … 0°

Feb

-7° … 3°

Mar

0° … 10°

Apr

4° … 15°

May

11° … 22°

Jun

17° … 28°

Jul

19° … 29°

Aug

18° … 28°

Sep

15° … 25°

Oct

8° … 17°

Nov

1° … 9°

Dec

-3° … 4°

Precipitation by month

monthly totals across the year

Jan

62 mm

Feb

58 mm

Mar

91 mm

Apr

95 mm

May

136 mm

Jun

121 mm

Jul

140 mm

Aug

101 mm

Sep

114 mm

Oct

112 mm

Nov

56 mm

Dec

65 mm

The short version

RegionIllinois

Latitude41.7859°N

Annual mean10.9°C

Annual precipitation1151 mm

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Weather map — Naperville

Naperville →

Source · 1991-2020 normals

Naperville, IL Climate