Normal climate — normals and trends
Normal (United States) has a hot-summer humid continental climate (Dfa) under the Köppen-Geiger classification. Its mean annual temperature is 10.8 °C and it receives 968 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 (23.8 °C on average) and the coldest is January (-4.1 °C). Rainfall peaks in May.
Normal averages 111 frost days, 31 hot days (≥ 30 °C) and 115 rainy days per year.
Normal 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 123 to 99 per year over the period.
The hottest day of the period reached 39.2 °C (on 7 July 2012) and the coldest -31.1 °C (on 20 January 1985).
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
NormalIllinois
- coords
- 40.51°, -88.99°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
10.8°C
Average daily high
15.7°C
Average daily low
6.1°C
Annual rainfall
968mm
Sunshine / day
8.9h
Mean relative humidity
70%
Average peak wind
20.6km/h
Seasonal range
27.9°C
Frost days (< 0 °C)
111 d/yr
Hot days (≥ 30 °C)
31 d/yr
Rainy days (≥ 1 mm)
115 d/yr
Annual snowfall
56.6 cm
Average feels-like high
13.7 °C
Average feels-like low
3.2 °C
Average peak gust
39.3 km/h
Tropical nights (≥ 20 °C)
34 d/yr
Solar radiation
15.3 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
39.2 °C
7 July 2012
Coldest day
-31.1 °C
20 January 1985
Wettest day
92 mm
21 August 2010
Windiest day
55.7 km/h
15 December 1971
Strongest gust
109.8 km/h
10 November 1998
Hottest feels-like
44.6 °C
14 July 1995
Coldest feels-like
-38.6 °C
20 January 1985
Snowiest day
23.7 cm
2 January 1999
Sunniest day
14.1 h
11 June 2025
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 | -0.7 °C | -0.6 °C | 27 mm | -26 mm |
| Feb | 2.9 °C | +0.4 °C | 19 mm | -35 mm |
| Mar | 14.5 °C | +5.5 °C | 90 mm | +4 mm |
| Apr | 17.6 °C | +1.3 °C | 109 mm | +3 mm |
| May | 22.3 °C | +0.3 °C | 85 mm | -25 mm |
| Jun | 28.4 °C | +1.5 °C | 121 mm | +19 mm |
| Jul | 30.0 °C | +1.5 °C | 138 mm | +49 mm |
| Aug | 27.4 °C | -0.4 °C | 57 mm | -22 mm |
| Sep | 27.6 °C | +3.0 °C | 33 mm | -45 mm |
| Oct | 21.0 °C | +2.9 °C | 87 mm | +10 mm |
| Nov | 11.0 °C | +1.4 °C | 59 mm | -14 mm |
| Dec | 2.4 °C | -0.3 °C | 49 mm | -12 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 Normal?
Normal has a hot-summer humid continental climate (Köppen Dfa). Over 1940-2025, the average annual temperature is 10.8 °C and it receives 968 mm of precipitation per year.
What is the hottest day ever recorded in Normal?
The hottest day measured in Normal between 1940 and 2025 was 7 July 2012, reaching 39.2 °C.
What is the coldest day in Normal?
The coldest day measured in Normal between 1940 and 2025 was 20 January 1985, at -31.1 °C.
Does it snow in Normal?
Yes. Normal gets on average 56.6 cm of snow per year and has around 111 frost days.
Has the climate of Normal warmed?
Yes: Normal warmed by +2.0 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Normal?
The wettest day measured in Normal between 1940 and 2025 was 21 August 2010, with 92 mm of rain in 24 hours.
What was the windiest day in Normal?
The windiest day measured in Normal between 1940 and 2025 was 15 December 1971, with winds reaching 55.7 km/h.
What is the warmest month in Normal?
The warmest month in Normal is July (23.8 °C on average); the coldest is January (-4.1 °C).
How much does it rain in Normal?
Normal receives on average 968 mm of precipitation per year, spread over about 115 rainy days.
Is it sunny in Normal?
Normal gets on average 8.9 hours of sunshine per day, roughly 3,249 hours per year over 1940-2025.
What is the biggest single-day snowfall in Normal?
The heaviest 24-hour snowfall measured in Normal between 1940 and 2025 was 2 January 1999, with 23.7 cm.
Are there tropical nights in Normal?
Yes: Normal has on average 34 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Normal?
In Normal, between 1940 and 2025, the highest apparent temperature reached 44.6 °C on 14 July 1995, and the lowest was -38.6 °C on 20 January 1985.
Compare Normal with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Normal