West Allis climate — normals and trends
West Allis (United States) has a hot-summer humid continental climate (Dfa) under the Köppen-Geiger classification. Its mean annual temperature is 8.5 °C and it receives 849 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 (22.4 °C on average) and the coldest is January (-5.9 °C). Rainfall peaks in April.
West Allis averages 120 frost days, 8 hot days (≥ 30 °C) and 117 rainy days per year.
West Allis has warmed by +1.7 °C between 1940 and 2025, or +0.20 °C per decade. This trend is statistically significant.
The number of frost days there went from about 136 to 104 per year over the period.
The hottest day of the period reached 37.0 °C (on 14 July 1995) and the coldest -30.8 °C (on 3 February 1996).
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
West AllisWisconsin
- coords
- 43.02°, -88.01°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
8.5°C
Average daily high
12.0°C
Average daily low
5.1°C
Annual rainfall
849mm
Sunshine / day
8.8h
Mean relative humidity
72%
Average peak wind
22.5km/h
Seasonal range
28.3°C
Frost days (< 0 °C)
120 d/yr
Hot days (≥ 30 °C)
8 d/yr
Rainy days (≥ 1 mm)
117 d/yr
Annual snowfall
89.0 cm
Average feels-like high
9.5 °C
Average feels-like low
1.6 °C
Average peak gust
39.9 km/h
Tropical nights (≥ 20 °C)
28 d/yr
Solar radiation
14.6 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.7 °C
since 1940
+0.2 °C per decade · r² = 0.28 · 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
37.0 °C
14 July 1995
Coldest day
-30.8 °C
3 February 1996
Wettest day
95 mm
13 September 1961
Windiest day
58.5 km/h
11 November 1940
Strongest gust
106.6 km/h
10 November 1998
Hottest feels-like
42.7 °C
13 July 1995
Coldest feels-like
-38.7 °C
20 January 1985
Snowiest day
25.1 cm
15 December 1987
Sunniest day
14.8 h
14 June 2020
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 | -2.0 °C | +0.6 °C | 7 mm | -43 mm |
| Feb | -0.6 °C | +0.7 °C | 29 mm | -13 mm |
| Mar | 8.5 °C | +4.8 °C | 96 mm | +28 mm |
| Apr | 11.1 °C | +1.1 °C | 56 mm | -37 mm |
| May | 14.5 °C | -1.7 °C | 96 mm | +11 mm |
| Jun | 23.3 °C | +0.5 °C | 86 mm | +3 mm |
| Jul | 25.8 °C | -0.2 °C | 112 mm | +29 mm |
| Aug | 24.4 °C | -0.9 °C | 91 mm | +10 mm |
| Sep | 22.2 °C | +0.9 °C | 54 mm | -23 mm |
| Oct | 16.4 °C | +1.6 °C | 42 mm | -28 mm |
| Nov | 8.0 °C | +1.1 °C | 56 mm | -8 mm |
| Dec | -0.4 °C | -0.8 °C | 60 mm | +5 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 West Allis?
West Allis has a hot-summer humid continental climate (Köppen Dfa). Over 1940-2025, the average annual temperature is 8.5 °C and it receives 849 mm of precipitation per year.
What is the hottest day ever recorded in West Allis?
The hottest day measured in West Allis between 1940 and 2025 was 14 July 1995, reaching 37.0 °C.
What is the coldest day in West Allis?
The coldest day measured in West Allis between 1940 and 2025 was 3 February 1996, at -30.8 °C.
Does it snow in West Allis?
Yes. West Allis gets on average 89.0 cm of snow per year and has around 120 frost days.
Has the climate of West Allis warmed?
Yes: West Allis warmed by +1.7 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in West Allis?
The wettest day measured in West Allis between 1940 and 2025 was 13 September 1961, with 95 mm of rain in 24 hours.
What was the windiest day in West Allis?
The windiest day measured in West Allis between 1940 and 2025 was 11 November 1940, with winds reaching 58.5 km/h.
What is the warmest month in West Allis?
The warmest month in West Allis is July (22.4 °C on average); the coldest is January (-5.9 °C).
How much does it rain in West Allis?
West Allis receives on average 849 mm of precipitation per year, spread over about 117 rainy days.
Is it sunny in West Allis?
West Allis 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 West Allis?
The heaviest 24-hour snowfall measured in West Allis between 1940 and 2025 was 15 December 1987, with 25.1 cm.
Are there tropical nights in West Allis?
Yes: West Allis has on average 28 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in West Allis?
In West Allis, between 1940 and 2025, the highest apparent temperature reached 42.7 °C on 13 July 1995, and the lowest was -38.7 °C on 20 January 1985.
Compare West Allis with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around West Allis