Chicago Waukegan Regional Airport, Illinois climate: Climate normals at a NOAA weather station
Chicago Waukegan Regional Airport's normal year runs from 16°F January nights to 81°F July afternoons, with 35.3 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 9.1°C, January lows of −9°C, July highs of 27°C, 897 mm of precipitation a year.
- NOAA stationChicago Waukegan Regional Airport
- Station IDUSW00014880
- Location42.42°N 87.87°W
- Elevation727 ft (222 m)
On October 23, the normal high in Chicago Waukegan Regional Airport is 58°F and the normal low 40°F, and the chance of measurable rain or snow is 35%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Chicago Waukegan Regional Airport.
- Jan 31° 16°
- Feb 34° 18°
- Mar 44° 27°
- Apr 56° 36°
- May 67° 46°
- Jun 77° 56°
- Jul 81° 62°
- Aug 80° 61°
- Sep 73° 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 at Chicago Waukegan Regional Airport each month?
July is the warmest month, with normal highs of 81°F; January the coldest, with normal lows of 16°F. The most precipitation falls in June (4.45 in), the least in January (1.41 in).
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 31°F | 16°F | 23.4°F | 1.41 | 8 | <1 | 28 | 9 h 20 min |
| February | 34°F | 18°F | 26.3°F | 1.52 | 9 | <1 | 26 | 10 h 30 min |
| March | 44°F | 27°F | 35.6°F | 2.22 | 11 | <1 | 22 | 11 h 50 min |
| April | 56°F | 36°F | 45.8°F | 3.77 | 12 | <1 | 9 | 13 h 20 min |
| May | 67°F | 46°F | 56.3°F | 3.92 | 14 | <1 | 1 | 14 h 30 min |
| June | 77°F | 56°F | 66.3°F | 4.45 | 12 | 2 | <1 | 15 h 20 min |
| July | 81°F | 62°F | 71.6°F | 3.48 | 10 | 4 | <1 | 15 h |
| August | 80°F | 61°F | 70.5°F | 3.59 | 13 | 3 | <1 | 14 h |
| September | 73°F | 54°F | 63.4°F | 3.57 | 12 | 1 | <1 | 12 h 30 min |
| October | 61°F | 43°F | 51.8°F | 3.25 | 12 | <1 | 4 | 11 h 10 min |
| November | 48°F | 31°F | 39.5°F | 2.26 | 10 | <1 | 16 | 9 h 50 min |
| December | 36°F | 22°F | 28.9°F | 1.86 | 9 | <1 | 26 | 9 h 10 min |
| Year (annual) | 57°F | 39°F | 48.3°F | 35.30 | 129 | 9 | 132 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | −1°C | −9°C | −4.8°C | 36 mm |
| February | 1°C | −8°C | −3.2°C | 39 mm |
| March | 7°C | −3°C | 2.0°C | 56 mm |
| April | 13°C | 2°C | 7.7°C | 96 mm |
| May | 19°C | 8°C | 13.5°C | 100 mm |
| June | 25°C | 13°C | 19.1°C | 113 mm |
| July | 27°C | 17°C | 22.0°C | 88 mm |
| August | 27°C | 16°C | 21.4°C | 91 mm |
| September | 23°C | 12°C | 17.4°C | 91 mm |
| October | 16°C | 6°C | 11.0°C | 83 mm |
| November | 9°C | 0°C | 4.2°C | 57 mm |
| December | 2°C | −6°C | −1.7°C | 47 mm |
NOAA publishes no 1991-2020 snowfall normal for this station. The nearest record that keeps one, Lake Villa (10 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 USW00014880; 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.
Which months are mildest at Chicago Waukegan Regional Airport?
Normal highs sit between 65°F and 85°F in May, June, July, August and September. Of those, July has the fewest days with rain (10).
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 USW00014880.
When is the last frost at Chicago Waukegan Regional Airport?
In Chicago Waukegan Regional Airport, the last spring frost (32°F) comes after April 30 in half of years and after May 16 in one year in ten; the first autumn frost comes before October 21 in half of years and before October 5 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 16; 9 in 10 after April 14
- First autumn frost, half of years before
- October 211 year in 10 before October 5; 9 in 10 before November 2
NOAA puts the median frost-free season at 173 days, and the season without a hard freeze (28°F) at 197 days.
A hard freeze (28°F) comes after April 16 in half of springs and before November 1 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Chicago Waukegan Regional Airport in zone 6a in ZIP code 60087, the nearest ZIP area. By the map's own method, the average of each year's coldest night over 1991-2020, the station is in zone 6a: the coldest night of a typical year reaches −9°F (20 complete years).
Frost dates for every NOAA station in Illinois · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USW00014880; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; the station zone: ACIS daily lows, 1991-2020. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
How hot and how cold does it get at Chicago Waukegan Regional Airport?
In a normal year in Chicago Waukegan Regional Airport, 9 days a year reach 90°F, 132 nights fall to 32°F or colder and 129 days bring measurable precipitation.
- Days at 90°F or more
- 9a normal year
- Days at 100°F or more
- fewer than 1a normal year
- Nights at 32°F or colder
- 132a normal year
- Days that stay below freezing
- 49high of 32°F or less
- Days with 0.01 inch of precipitation
- 129a normal year
The highest temperature in this station's record (since 1999) is 104°F, on July 5, 2012; the lowest is −23°F, on January 31, 2019.
The wettest calendar year on that record is 2018, with 48.72 in.
Source: NOAA NCEI 1991-2020 annual normals, station USW00014880; records: ACIS (NOAA Regional Climate Centers), station USW00014880. Records use complete months only; a month missing more than three days is left out.
How sunny is it at Chicago Waukegan Regional Airport?
Over a year 70% of the sunlight that would reach the ground under clear skies gets through the clouds at Chicago Waukegan Regional Airport, 3.7 kWh per square metre a day. July is the sunniest month (79%) and January the cloudiest (53%).
| 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 many heating and cooling degree days does Chicago Waukegan Regional Airport record?
A normal year at Chicago Waukegan Regional Airport brings 6,688 heating degree days, 24% more than the median U.S. place (5,373), and 626 cooling degree days, 31% 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 2,670 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 1,288 | 0 |
| February | 1,085 | 0 |
| March | 912 | 1 |
| April | 581 | 4 |
| May | 298 | 27 |
| June | 73 | 113 |
| July | 13 | 218 |
| August | 12 | 184 |
| September | 121 | 71 |
| October | 418 | 8 |
| November | 767 | 0 |
| December | 1,121 | 0 |
| Year (annual) | 6,688 | 626 |
Source: NOAA NCEI 1991-2020 monthly normals, station USW00014880. 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.
Have recent years at Chicago Waukegan Regional Airport been warmer than normal?
2025 averaged 49.6°F, 1.3°F above the 1991-2020 normal of 48.3°F. 5 of the 5 complete years since 2021 ran warmer than the normal.
| Year | Mean | Against normal | Precip. |
|---|---|---|---|
| 2021 | 50.7°F | +2.4°F | 22.62 |
| 2022 | 48.6°F | +0.3°F | 33.30 |
| 2023 | 51.3°F | +3.0°F | 35.08 |
| 2024 | 52.2°F | +3.9°F | 40.53 |
| 2025 | 49.6°F | +1.3°F | 27.63 |
Source: observed years: ACIS, station USW00014880. A year counts only with all twelve months complete.
How does Chicago Waukegan Regional Airport's climate compare?
Chicago Waukegan Regional Airport is warmer than 11 of the 144 places with their own NOAA record in Illinois, and wetter than 3. Across the 7,247 U.S. stations with normals, its annual mean of 48.3°F is warmer than 33%.
In the Köppen classification computed from these normals, Chicago Waukegan Regional Airport is Dfb: continental, no dry season, warm summer. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Chicago Waukegan Regional Airport share this climate record?
Pleasant Prairie has no NOAA station with 1991-2020 normals of its 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.
- Pleasant Prairie, WI21,802 people · 8 mi N
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 Chicago Waukegan Regional Airport's climate
What is the coldest month at Chicago Waukegan Regional Airport?
January, with a normal high of 31°F and a normal low of 16°F. The warmest is July (81°F by day, 62°F at night).
Does it snow at Chicago Waukegan Regional Airport?
Yes. NOAA publishes no 1991-2020 snowfall normal for the station; the nearest record that keeps one, Lake Villa (10 miles away), records 43 inches of snow in a normal year.
What is the rainiest month at Chicago Waukegan Regional Airport?
June, with 4.45 in of precipitation in a normal year; the driest is January with 1.41 in.
What plant hardiness zone is Chicago Waukegan Regional Airport in?
The USDA's 2023 map puts Chicago Waukegan Regional Airport in zone 6a in ZIP code 60087, the nearest ZIP area. By the same method at the station, the coldest night of a typical year reaches −9°F (20 years, 1991-2020): zone 6a.
How late can frost come at Chicago Waukegan Regional Airport?
In half of years the last 32°F night comes after April 30; in one year in ten it comes after May 16. Waiting until May 16 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Illinois climateThe statewide normals and every place in the state
- Waukegan, IL5 miles from this station, 48.4°F a year
- Lake Villa, IL10 miles from this station, 48.6°F a year
- Antioch, IL12 miles from this station, 48.6°F a year
- Kenosha, WI13 miles from this station, 49.2°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made