Prospect Heights climate — normals and trends
Prospect Heights (United States) has a hot-summer humid continental climate (Dfa) under the Köppen-Geiger classification. Its mean annual temperature is 9.6 °C and it receives 892 mm of precipitation per year.
These figures are normals computed over 86 complete calendar years, from 1940 to 2025, using ERA5 reanalysis data from the Copernicus programme.
The warmest month is July (23.2 °C on average) and the coldest is January (-5.2 °C). Rainfall peaks in April.
Prospect Heights averages 120 frost days, 25 hot days (≥ 30 °C) and 116 rainy days per year.
Prospect Heights has warmed by +2.0 °C between 1940 and 2025, or +0.24 °C per decade. This trend is statistically significant.
The number of frost days there went from about 135 to 105 per year over the period.
The hottest day of the period reached 39.0 °C (on 25 June 1988) and the coldest -32.9 °C (on 31 January 2019).
Data from ERA5 reanalysis (Copernicus Climate Change Service), redistributed under a CC-BY 4.0 licence. Normals are recomputed whenever the archive is updated.
Climate normals · ERA5
Prospect HeightsIllinois
- coords
- 42.10°, -87.94°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
9.6°C
Average daily high
14.1°C
Average daily low
5.3°C
Annual rainfall
892mm
Sunshine / day
8.8h
Mean relative humidity
71%
Average peak wind
19.5km/h
Seasonal range
28.4°C
Frost days (< 0 °C)
120 d/yr
Hot days (≥ 30 °C)
25 d/yr
Rainy days (≥ 1 mm)
116 d/yr
Annual snowfall
76.6 cm
Average feels-like high
12.1 °C
Average feels-like low
2.3 °C
Average peak gust
40.1 km/h
Tropical nights (≥ 20 °C)
28 d/yr
Solar radiation
14.9 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+2.0 °C
since 1940
+0.2 °C per decade · r² = 0.37 · p = < 0.001
Trend fitted by linear regression (ordinary least squares) on annual means. A trend is shown only when it is statistically significant (p < 0.05).
A climograph overlays rainfall (bars) and temperature (line): the standard reading in climatology, where you can see at a glance whether the warm season is also the dry one.
Records for the period
Hottest day
39.0 °C
25 June 1988
Coldest day
-32.9 °C
31 January 2019
Wettest day
93 mm
30 August 1975
Windiest day
52.2 km/h
11 November 1940
Strongest gust
112.0 km/h
10 November 1998
Hottest feels-like
44.5 °C
6 July 2012
Coldest feels-like
-38.7 °C
31 January 2019
Snowiest day
24.9 cm
1 December 2006
Sunniest day
14.6 h
14 June 2019
Normals computed over complete calendar years 1940–2025.
A specific year
Pick a year and see how it compares to normal — warmer, drier or more extreme than usual?
Across the whole year
Month by month
| High | vs. normal | Precipitation | vs. normal | |
|---|---|---|---|---|
| Jan | -1.2 °C | +0.3 °C | 43 mm | -7 mm |
| Feb | 0.9 °C | +0.2 °C | 26 mm | -19 mm |
| Mar | 12.4 °C | +5.6 °C | 93 mm | +21 mm |
| Apr | 15.0 °C | +1.2 °C | 73 mm | -26 mm |
| May | 18.4 °C | -1.6 °C | 97 mm | +0 mm |
| Jun | 27.7 °C | +2.0 °C | 123 mm | +29 mm |
| Jul | 28.9 °C | +1.0 °C | 129 mm | +40 mm |
| Aug | 26.5 °C | -0.5 °C | 87 mm | +2 mm |
| Sep | 25.1 °C | +2.0 °C | 40 mm | -34 mm |
| Oct | 18.3 °C | +1.7 °C | 66 mm | -3 mm |
| Nov | 9.3 °C | +1.1 °C | 56 mm | -7 mm |
| Dec | 0.9 °C | -0.4 °C | 60 mm | +4 mm |
The year's extremes
What was the weather like that day?
Your birthday, a wedding, a memorable trip: discover the actual weather for any date since 1940.
Frequently asked questions
What is the climate of Prospect Heights?
Prospect Heights has a hot-summer humid continental climate (Köppen Dfa). Over 1940-2025, the average annual temperature is 9.6 °C and it receives 892 mm of precipitation per year.
What is the hottest day ever recorded in Prospect Heights?
The hottest day measured in Prospect Heights between 1940 and 2025 was 25 June 1988, reaching 39.0 °C.
What is the coldest day in Prospect Heights?
The coldest day measured in Prospect Heights between 1940 and 2025 was 31 January 2019, at -32.9 °C.
Does it snow in Prospect Heights?
Yes. Prospect Heights gets on average 76.6 cm of snow per year and has around 120 frost days.
Has the climate of Prospect Heights warmed?
Yes: Prospect Heights warmed by +2.0 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Prospect Heights?
The wettest day measured in Prospect Heights between 1940 and 2025 was 30 August 1975, with 93 mm of rain in 24 hours.
What was the windiest day in Prospect Heights?
The windiest day measured in Prospect Heights between 1940 and 2025 was 11 November 1940, with winds reaching 52.2 km/h.
What is the warmest month in Prospect Heights?
The warmest month in Prospect Heights is July (23.2 °C on average); the coldest is January (-5.2 °C).
How much does it rain in Prospect Heights?
Prospect Heights receives on average 892 mm of precipitation per year, spread over about 116 rainy days.
Is it sunny in Prospect Heights?
Prospect Heights gets on average 8.8 hours of sunshine per day, roughly 3,212 hours per year over 1940-2025.
What is the biggest single-day snowfall in Prospect Heights?
The heaviest 24-hour snowfall measured in Prospect Heights between 1940 and 2025 was 1 December 2006, with 24.9 cm.
Are there tropical nights in Prospect Heights?
Yes: Prospect Heights has on average 28 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Prospect Heights?
In Prospect Heights, between 1940 and 2025, the highest apparent temperature reached 44.5 °C on 6 July 2012, and the lowest was -38.7 °C on 31 January 2019.
Compare Prospect Heights with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Prospect Heights