Ann Arbor climate — normals and trends
Ann Arbor (United States) has a hot-summer humid continental climate (Dfa) under the Köppen-Geiger classification. Its mean annual temperature is 9.2 °C and it receives 887 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 (22.1 °C on average) and the coldest is January (-4.5 °C). Rainfall peaks in May.
Ann Arbor averages 127 frost days, 18 hot days (≥ 30 °C) and 121 rainy days per year.
Ann Arbor has warmed by +1.9 °C between 1940 and 2025, or +0.23 °C per decade. This trend is statistically significant.
The number of frost days there went from about 141 to 113 per year over the period.
The hottest day of the period reached 39.1 °C (on 25 June 1988) and the coldest -29.2 °C (on 20 February 2015).
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
Ann ArborMichigan
- coords
- 42.28°, -83.74°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
9.2°C
Average daily high
13.9°C
Average daily low
4.5°C
Annual rainfall
887mm
Sunshine / day
8.6h
Mean relative humidity
72%
Average peak wind
18.6km/h
Seasonal range
26.6°C
Frost days (< 0 °C)
127 d/yr
Hot days (≥ 30 °C)
18 d/yr
Rainy days (≥ 1 mm)
121 d/yr
Annual snowfall
80.4 cm
Average feels-like high
11.8 °C
Average feels-like low
1.5 °C
Average peak gust
38.7 km/h
Tropical nights (≥ 20 °C)
16 d/yr
Solar radiation
14.4 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.9 °C
since 1940
+0.2 °C per decade · r² = 0.39 · 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
39.1 °C
25 June 1988
Coldest day
-29.2 °C
20 February 2015
Wettest day
82 mm
25 June 1968
Windiest day
53.9 km/h
22 March 1955
Strongest gust
107.3 km/h
19 March 1948
Hottest feels-like
43.8 °C
14 July 1995
Coldest feels-like
-34.7 °C
31 January 2019
Snowiest day
26.1 cm
26 January 1978
Sunniest day
14.9 h
23 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 | -1.9 °C | -1.0 °C | 38 mm | -19 mm |
| Feb | 0.0 °C | -0.7 °C | 46 mm | -6 mm |
| Mar | 11.7 °C | +5.1 °C | 76 mm | +5 mm |
| Apr | 15.5 °C | +1.8 °C | 85 mm | -3 mm |
| May | 18.6 °C | -1.4 °C | 122 mm | +29 mm |
| Jun | 26.7 °C | +1.5 °C | 131 mm | +41 mm |
| Jul | 28.4 °C | +1.0 °C | 124 mm | +41 mm |
| Aug | 25.9 °C | -0.5 °C | 39 mm | -41 mm |
| Sep | 24.6 °C | +2.1 °C | 47 mm | -22 mm |
| Oct | 18.2 °C | +2.3 °C | 72 mm | +4 mm |
| Nov | 8.1 °C | 0.0 °C | 45 mm | -26 mm |
| Dec | 1.1 °C | -0.5 °C | 78 mm | +15 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 Ann Arbor?
Ann Arbor has a hot-summer humid continental climate (Köppen Dfa). Over 1940-2025, the average annual temperature is 9.2 °C and it receives 887 mm of precipitation per year.
What is the hottest day ever recorded in Ann Arbor?
The hottest day measured in Ann Arbor between 1940 and 2025 was 25 June 1988, reaching 39.1 °C.
What is the coldest day in Ann Arbor?
The coldest day measured in Ann Arbor between 1940 and 2025 was 20 February 2015, at -29.2 °C.
Does it snow in Ann Arbor?
Yes. Ann Arbor gets on average 80.4 cm of snow per year and has around 127 frost days.
Has the climate of Ann Arbor warmed?
Yes: Ann Arbor warmed by +1.9 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Ann Arbor?
The wettest day measured in Ann Arbor between 1940 and 2025 was 25 June 1968, with 82 mm of rain in 24 hours.
What was the windiest day in Ann Arbor?
The windiest day measured in Ann Arbor between 1940 and 2025 was 22 March 1955, with winds reaching 53.9 km/h.
What is the warmest month in Ann Arbor?
The warmest month in Ann Arbor is July (22.1 °C on average); the coldest is January (-4.5 °C).
How much does it rain in Ann Arbor?
Ann Arbor receives on average 887 mm of precipitation per year, spread over about 121 rainy days.
Is it sunny in Ann Arbor?
Ann Arbor gets on average 8.6 hours of sunshine per day, roughly 3,139 hours per year over 1940-2025.
What is the biggest single-day snowfall in Ann Arbor?
The heaviest 24-hour snowfall measured in Ann Arbor between 1940 and 2025 was 26 January 1978, with 26.1 cm.
Are there tropical nights in Ann Arbor?
Yes: Ann Arbor has on average 16 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Ann Arbor?
In Ann Arbor, between 1940 and 2025, the highest apparent temperature reached 43.8 °C on 14 July 1995, and the lowest was -34.7 °C on 31 January 2019.
Compare Ann Arbor with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Ann Arbor