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Waukegan, Illinois climate

Dfa Hot-summer humid continental

Waukegan has a strongly seasonal cool-temperate climate (Hot-summer humid continental, Köppen Dfa). The hottest month is July with an average daily high near 84°F, while the coldest is January averaging around 18°F at night. Around 32 inches of precipitation falls each year, peaking in June (4.0 inches) and easing off in February (1.3 inches).

☀️ Summers

Warm

Highs near 84°F in July.

About 17 days a year above 90 °F

❄️ Winters

Very cold

Lows near 18°F in January.

About 118 freezing nights a year

🌧️ Rain

Moderate rainfall

About 32 in of rain a year.

Wettest in June

⛅ Sky & trend

Often cloudy

Cloudy skies much of the year.

+0.7 °F vs 50 years ago

Temperature & precipitation

Daily high–low temperature range with the monthly average, plus monthly precipitation · 1991–2020 normals · hover a month for the exact figures

Clear vs cloudy days

Share of days each month that are clear, partly cloudy or cloudy · 1991–2020 · hover a month for the day counts

Waukegan climate normals (1991–2020)

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Avg high (°F)	32	36	47	58	70	80	84	82	75	63	49	37
Avg temp (°F)	25	29	38	49	60	70	75	73	66	54	41	30
Avg low (°F)	18	21	30	39	50	60	66	65	56	45	33	24
Precipitation (in)	1.3	1.3	1.8	3.3	3.8	4.0	3.2	3.7	3.0	3.1	2.2	1.6

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Avg high (°F)	32	36	47	58	70	80
Avg temp (°F)	25	29	38	49	60	70
Avg low (°F)	18	21	30	39	50	60
Precipitation (in)	1.3	1.3	1.8	3.3	3.8	4.0

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Avg high (°F)	84	82	75	63	49	37
Avg temp (°F)	75	73	66	54	41	30
Avg low (°F)	66	65	56	45	33	24
Precipitation (in)	3.2	3.7	3.0	3.1	2.2	1.6

How often — frequency of weather events

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Days with measurable rain (days)	6	5	8	10	11	10	8	8	9	10	8	7
Days with high ≥ 90°F (days)	—	—	—	—	0.7	4	7	4	2	—	0.0	—
Days with low ≤ 32°F (days)	26	24	19	6	0.1	—	—	—	0.0	2	15	25

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Days with measurable rain (days)	6	5	8	10	11	10
Days with high ≥ 90°F (days)	—	—	—	—	0.7	4
Days with low ≤ 32°F (days)	26	24	19	6	0.1	—

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Days with measurable rain (days)	8	8	9	10	8	7
Days with high ≥ 90°F (days)	7	4	2	—	0.0	—
Days with low ≤ 32°F (days)	—	—	0.0	2	15	25

Sky & atmosphere

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Cloud cover (%)	76	73	76	80	79	76	68	64	59	65	70	75
Clear days (≤ 30% cloud)	1	2	0.9	1	2	2	3	4	7	6	3	2
Partly cloudy days (30–70%)	9	9	10	7	7	8	11	12	10	9	9	8
Cloudy days (≥ 70%)	21	17	20	22	22	20	17	15	13	16	17	20
Relative humidity (%)	88	85	80	76	75	74	73	73	73	76	81	87
Wind speed (mph)	9.1	9.0	8.7	8.7	7.4	6.2	5.5	5.3	6.1	7.3	8.1	8.3

Jan – Jun	Jan	Feb	Mar	Apr	May	Jun
Cloud cover (%)	76	73	76	80	79	76
Clear days (≤ 30% cloud)	1	2	0.9	1	2	2
Partly cloudy days (30–70%)	9	9	10	7	7	8
Cloudy days (≥ 70%)	21	17	20	22	22	20
Relative humidity (%)	88	85	80	76	75	74
Wind speed (mph)	9.1	9.0	8.7	8.7	7.4	6.2

Jul – Dec	Jul	Aug	Sep	Oct	Nov	Dec
Cloud cover (%)	68	64	59	65	70	75
Clear days (≤ 30% cloud)	3	4	7	6	3	2
Partly cloudy days (30–70%)	11	12	10	9	9	8
Cloudy days (≥ 70%)	17	15	13	16	17	20
Relative humidity (%)	73	73	73	76	81	87
Wind speed (mph)	5.5	5.3	6.1	7.3	8.1	8.3

Methodology & sources

Temperature & precipitation — the official 1991–2020 climate normals from NOAA's U.S. Climate Normals, measured at Chicago Palwaukee AP (NOAA GHCN station USW00004838), about 27 km from the city centre.

Cloud, humidity, wind & sunshine — modelled estimates from NASA POWER, NASA's satellite-and-reanalysis climatology. This is the standard global source for atmospheric variables, which are not measured at most weather stations.

How we build these numbers →