ClimateAverages

Waukegan Climate

Illinois, United States of America · population 88,475 · 384 weather stations within 200 km · records 1787 to 2025

Average annual daytime high
13.5°C
Warmest month · July
27.3°C
Typical daytime high
Coldest month · January
-10.2°C
Typical overnight low

Waukegan has an average annual daytime high of 13.5°C, based on the 1951 to 1980 baseline. Its warmest month is July, when highs typically reach 27.3°C, and its coldest is January, with overnight lows near -10.2°C.

Month by month averages

MonthAvg highAvg low
January-2.0°C-10.2°CColdest
February0.3°C-8.0°C
March5.2°C-3.1°C
April12.7°C2.8°C
May19.0°C8.3°C
June24.7°C14.0°C
July27.3°C17.1°CWarmest
August26.6°C16.7°C
September22.7°C12.4°C
October16.2°C6.3°C
November8.0°C-0.2°C
December1.0°C-6.5°C

Temperature range across the year

-12°-2°9°19°29°JanFebMarAprMayJunJulAugSepOctNovDec
Daytime high Overnight low
Hottest year on record
2011
+2.8°C vs. 1951–1980
Coldest year on record
1836
-2.6°C vs. 1951–1980

These figures reflect annual averages, not single-day records. Daily observations are outside this dataset's precision.

Is Waukegan getting hotter?

Since 1900, Waukegan's average temperature has risen by +2.3°C. Compared to the earliest station records that begin in 1787, warming totals +2.4°C.

8.0°8.7°9.4°10.1°10.8°1951–1980 baseline190019251950197520002025

20-year smoothed annual temperature reconstructed from station anomalies. Dashed line: 1951–1980 baseline.

Best time to visit
May to October

Daytime highs sit within a comfortable 15°C to 26°C range.

FAQ

What is the average temperature in Waukegan?

Waukegan's average annual daytime high is 13.5°C, based on the 1951 to 1980 baseline period. The warmest month is July, with highs averaging 27.3°C, and the coldest is January, with lows averaging -10.2°C.

What is the warmest month in Waukegan?

July is the warmest month in Waukegan, with typical daytime highs of 27.3°C.

What is the hottest year on record for Waukegan?

2011 is the hottest year on record for Waukegan, running +2.8°C above the 1951 to 1980 baseline.

Is Waukegan getting hotter?

Yes. Since 1900, Waukegan has warmed by roughly +2.3°C.

When is the best time to visit Waukegan?

May to October typically offers the most comfortable daytime highs, in the 15°C to 26°C range.

Nearby cities

Baseline period 1951 to 1980. Monthly averages are the mean of station observations weighted by proximity. Warming trend is the 20-year smoothed anomaly against that baseline.