Waukegan, Illinois climate: Normal weather by month, frost dates and records
Waukegan's normal year runs from 16°F January nights to 82°F July afternoons. (NOAA 1991-2020 normals)
In metric: a yearly mean of 9.1°C, January lows of −9°C, July highs of 28°C.
- NOAA stationWaukegan
- Station IDUSC00119029
- Location42.35°N 87.88°W
- Elevation700 ft (213 m)
- From the center2 miles
- Population88,570
On October 23, the normal high in Waukegan is 58°F and the normal low 41°F.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Waukegan.
- Jan 30° 16°
- Feb 34° 18°
- Mar 44° 27°
- Apr 55° 35°
- May 67° 47°
- Jun 76° 57°
- Jul 82° 63°
- Aug 80° 62°
- Sep 74° 54°
- Oct 61° 43°
- Nov 48° 31°
- Dec 36° 22°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Waukegan each month?
July is the warmest month, with normal highs of 82°F; January the coldest, with normal lows of 16°F.
| Month | High | Low | Mean | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|
| January | 30°F | 16°F | 22.7°F | – | <1 | 29 | 9 h 20 min |
| February | 34°F | 18°F | 25.8°F | – | <1 | 25 | 10 h 30 min |
| March | 44°F | 27°F | 35.8°F | – | <1 | 24 | 11 h 50 min |
| April | 55°F | 35°F | 45.3°F | – | <1 | 9 | 13 h 20 min |
| May | 67°F | 47°F | 57.4°F | – | 1 | 1 | 14 h 30 min |
| June | 76°F | 57°F | 66.6°F | – | 3 | <1 | 15 h 20 min |
| July | 82°F | 63°F | 72.4°F | – | 5 | <1 | 15 h |
| August | 80°F | 62°F | 70.7°F | – | 2 | <1 | 14 h |
| September | 74°F | 54°F | 63.8°F | – | 1 | <1 | 12 h 30 min |
| October | 61°F | 43°F | 52.1°F | – | <1 | 3 | 11 h 10 min |
| November | 48°F | 31°F | 39.5°F | – | <1 | 17 | 9 h 50 min |
| December | 36°F | 22°F | 28.6°F | – | <1 | 26 | 9 h 10 min |
| Year (annual) | 57°F | 40°F | 48.4°F | – | 11 | 133 |
The same normals in °C and millimetres
| Month | High | Low | Mean |
|---|---|---|---|
| January | −1°C | −9°C | −5.2°C |
| February | 1°C | −8°C | −3.4°C |
| March | 7°C | −3°C | 2.1°C |
| April | 13°C | 2°C | 7.4°C |
| May | 20°C | 9°C | 14.1°C |
| June | 25°C | 14°C | 19.2°C |
| July | 28°C | 17°C | 22.4°C |
| August | 27°C | 16°C | 21.5°C |
| September | 23°C | 12°C | 17.7°C |
| October | 16°C | 6°C | 11.2°C |
| November | 9°C | 0°C | 4.2°C |
| December | 2°C | −6°C | −1.9°C |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Lake Villa (11 miles away), gets 43 inches of snow in a normal year; elevation and distance can change that.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00119029; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Waukegan?
Normal highs sit between 65°F and 85°F in May, June, July, August and September.
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00119029.
When is the last frost in Waukegan?
In Waukegan, the last spring frost (32°F) comes after April 30 in half of years and after May 14 in one year in ten; the first autumn frost comes before October 19 in half of years and before September 30 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- April 301 year in 10 after May 14; 9 in 10 after April 15
- First autumn frost, half of years before
- October 191 year in 10 before September 30; 9 in 10 before November 3
NOAA puts the median frost-free season at 170 days, and the season without a hard freeze (28°F) at 191 days.
A hard freeze (28°F) comes after April 20 in half of springs and before October 30 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Waukegan in zone 6a across its 3 ZIP code areas (6a in 60085, the largest).
Frost dates for every NOAA station in Illinois · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00119029; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
What hardiness zone is each Waukegan ZIP code in?
The USDA's 2023 map gives each ZIP code area one zone. Waukegan's 3 ZIP code areas are all in zone 6a. Each ZIP's frost dates are in the frost tool.
Source: USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; ZIP areas in the place: Census Bureau 2020 ZCTA-to-place relationship file. A ZIP area counts when at least a tenth of its land (and 0.5 km²) lies in the place.
How hot and how cold does it get in Waukegan?
In a normal year in Waukegan, 11 days a year reach 90°F and 133 nights fall to 32°F or colder.
- Days at 90°F or more
- 11a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 133a normal year
- Days that stay below freezing
- 48high of 32°F or less
The highest temperature in this station's record (since 1923) is 108°F, on July 24, 1934; the lowest is −24°F, on January 11, 1982.
The wettest calendar year on that record is 1972, with 50.33 in; the snowiest season is 1964–65, with 75.0 inches.
Source: NOAA NCEI 1991-2020 annual normals, station USC00119029; records: ACIS (NOAA Regional Climate Centers), station USC00119029. Records use complete months only; a month missing more than three days is left out.
How sunny is Waukegan?
Over a year 70% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Waukegan, 3.7 kWh per square metre a day. July is the sunniest month (79%) and January the cloudiest (53%). Among the 459 U.S. places of 50,000 or more, that ranks tied 428th (with 16 others) in sunshine.
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 53% | 1.4 |
| February | 58% | 2.3 |
| March | 65% | 3.4 |
| April | 67% | 4.5 |
| May | 68% | 5.3 |
| June | 74% | 5.9 |
| July | 79% | 6.0 |
| August | 78% | 5.2 |
| September | 77% | 4.2 |
| October | 67% | 2.7 |
| November | 62% | 1.8 |
| December | 54% | 1.2 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Waukegan need?
A normal year in Waukegan brings 6,702 heating degree days, 25% more than the median U.S. place (5,373), and 683 cooling degree days, 25% fewer than the median (908). Seven months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 2,748 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,311 | 0 |
| February | 1,099 | 0 |
| March | 907 | 0 |
| April | 597 | 6 |
| May | 276 | 40 |
| June | 77 | 125 |
| July | 10 | 237 |
| August | 16 | 192 |
| September | 110 | 75 |
| October | 409 | 7 |
| November | 764 | 0 |
| December | 1,128 | 0 |
| Year (annual) | 6,702 | 683 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00119029. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
How does Waukegan's climate compare?
Waukegan is warmer than 12 of the other 143 places with their own NOAA record in Illinois. Across the 7,247 U.S. stations with normals, its annual mean of 48.4°F is warmer than 34%.
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers.
Which places near Waukegan share this climate record?
8 places have no NOAA station with 1991-2020 normals of their own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- North Chicago, IL30,639 people · 3 mi SE
- Gurnee, IL30,546 people · 3 mi NW
- Gages Lake, IL10,706 people · 5 mi W
- Park City, IL7,940 people · 1 mi NW
- Lake Bluff, IL5,600 people · 5 mi S
- Green Oaks, IL4,107 people · 4 mi SW
- Knollwood, IL1,907 people · 4 mi S
- Mettawa, IL562 people · 8 mi S
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Waukegan's climate
What is the coldest month in Waukegan?
January, with a normal high of 30°F and a normal low of 16°F. The warmest is July (82°F by day, 63°F at night).
Does it snow in Waukegan?
Yes. NOAA publishes no 1991-2020 snowfall normal for Waukegan's NOAA station; the nearest record that keeps one, Lake Villa (11 miles away), records 43 inches of snow in a normal year.
What plant hardiness zone is Waukegan in?
The USDA's 2023 map puts Waukegan in zone 6a across its 3 ZIP code areas (6a in 60085, the largest).
How late can frost come in Waukegan?
In half of years the last 32°F night comes after April 30; in one year in ten it comes after May 14. Waiting until May 14 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Illinois climateThe statewide normals and every place in the state
- Chicago Waukegan Regional Airport, IL5 miles from this station, 48.3°F a year
- Lake Villa, IL11 miles from this station, 48.6°F a year
- Mundelein, IL12 miles from this station, 47.9°F a year
- Antioch, IL14 miles from this station, 48.6°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made