Mount Prospect, Illinois climate: NOAA's gridded normals for the city, beside the nearest station records
NOAA's gridded 1991-2020 normals put Mount Prospect's center at January lows of 16°F and July highs of 84°F, a yearly mean of 49.7°F and 37.8 inches of precipitation. No NOAA station keeps a record under the city's name. The nearest station record, Wheeling (4 miles NE, 636 ft), has January lows of 18°F and July highs of 84°F.
55,460 people (Census Bureau 2024). Distances and directions are from the city's center.
- Jan 31° 16°
- Feb 35° 19°
- Mar 46° 28°
- Apr 58° 38°
- May 70° 49°
- Jun 80° 58°
- Jul 84° 64°
- Aug 82° 62°
- Sep 75° 55°
- Oct 62° 43°
- Nov 48° 32°
- Dec 36° 22°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
The months above are NOAA's gridded normals at Mount Prospect's center.
What is each month like in Mount Prospect?
NOAA's grid estimates the normals every 5 km or so from the stations around each point, terrain included. It smooths between stations, so night lows at the heart of a large city can run warmer than the grid shows: at five big-city airports we compared, the grid's highs were within about 1°F of the station and its lows 1-6°F cooler. The nearest record's high and low are beside each month.
| Month | High | Low | Mean | Precip. | Wheeling high | Wheeling low |
|---|---|---|---|---|---|---|
| January | 31°F | 16°F | 23.7°F | 1.91 | 32°F | 18°F |
| February | 35°F | 19°F | 27.3°F | 1.80 | 36°F | 21°F |
| March | 46°F | 28°F | 37.3°F | 2.28 | 47°F | 30°F |
| April | 58°F | 38°F | 48.2°F | 3.78 | 58°F | 39°F |
| May | 70°F | 49°F | 59.1°F | 4.53 | 70°F | 50°F |
| June | 80°F | 58°F | 68.9°F | 4.63 | 80°F | 60°F |
| July | 84°F | 64°F | 73.6°F | 3.86 | 84°F | 66°F |
| August | 82°F | 62°F | 72.0°F | 3.88 | 82°F | 65°F |
| September | 75°F | 55°F | 64.8°F | 3.36 | 75°F | 56°F |
| October | 62°F | 43°F | 52.5°F | 3.26 | 63°F | 45°F |
| November | 48°F | 32°F | 39.9°F | 2.42 | 49°F | 33°F |
| December | 36°F | 22°F | 29.1°F | 2.10 | 37°F | 24°F |
In metric: a yearly mean of 9.8°C, January lows of −9°C, July highs of 29°C and 960 mm of precipitation a year.
Source: NOAA NCEI U.S. Monthly Gridded Climate Normals 1991-2020 (nClimGrid, accession 0245564); NOAA NCEI 1991-2020 station normals. The grid cell holding the city's Census center point.
What do the station records around Mount Prospect say?
Each row is a NOAA station's own 1991-2020 normals, with the snow and frost dates the grid does not give. A record downhill or nearer the coast than the city can run warmer, one uphill cooler: compare the elevations.
| Record | Where | Elevation | Year | Jan low | Jul high | Precip. | Snow | Last frost |
|---|---|---|---|---|---|---|---|---|
| WheelingChicago Palwaukee Airport | 4 mi NE | 636 ft | 50.8°F | 18°F | 84°F | 32.3 | – | April 19 |
| ChicagoChicago O'Hare International Airport | 5 mi S | 658 ft | 51.2°F | 19°F | 85°F | 37.9 | 38 | April 16 |
| Chicago Botanic Garden | 9 mi NE | 630 ft | 49.6°F | 16°F | 84°F | 39.5 | 34 | April 26 |
Source: NOAA NCEI 1991-2020 U.S. Climate Normals; place center and population: Census Bureau 2024. Last frost: the median last spring date of 32°F.
How much snow, how late a frost, what zone and how much sun in Mount Prospect?
NOAA's grid gives no snow, frost dates or records, so these come from the nearest station record, Wheeling (4 miles NE, 636 ft). NOAA publishes no snowfall normal for it; the nearest record that has one, Chicago (5 miles S), gets 38 inches a year. The last spring frost (32°F) comes after April 19 in half of years and the first autumn frost before October 26. Its record high is 104°F (2012) and its record low −21°F (2019) (kept since 1996).
The USDA's 2023 Plant Hardiness Zone Map puts Mount Prospect in zone 6a (ZIP code 60056).
Over a year 70% of the sunlight that would reach the ground under clear skies gets through the clouds in the area (3.7 kWh per square metre a day, NASA POWER 2001-2020); July is the sunniest month (79%) and January the cloudiest (53%).
Wheeling's page has its months, frost probabilities, records by month and recent years. NOAA's grid has monthly figures only, so there are no day-by-day month pages for Mount Prospect; the nearest record's month pages have them.
Source: NOAA NCEI 1991-2020 normals, station USW00004838; records: ACIS; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; sunshine: NASA POWER.
How does the climate vary across Mount Prospect, ZIP code by ZIP code?
One ZIP code area lies wholly or partly in Mount Prospect. Each row also names the nearest station record and its frost dates.
Source: Census Bureau 2020 ZCTA-to-place relationship file and ZCTA centers; NOAA NCEI gridded and station normals, 1991-2020. A ZIP area counts when at least a tenth of its land (and 0.5 km²) is in the city; its figures are the grid cell at its center; frost dates are the nearest record's medians of 32°F.