Ames climate — normals and trends
Ames (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 922 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 (23.4 °C on average) and the coldest is January (-7.3 °C). Rainfall peaks in May.
Ames averages 133 frost days, 30 hot days (≥ 30 °C) and 105 rainy days per year.
Ames has warmed by +1.9 °C between 1940 and 2025, or +0.22 °C per decade. This trend is statistically significant.
The number of frost days there went from about 140 to 126 per year over the period.
The hottest day of the period reached 38.4 °C (on 15 August 1988) and the coldest -33.7 °C (on 16 January 2009).
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
AmesIowa
- coords
- 42.03°, -93.62°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
9.2°C
Average daily high
14.3°C
Average daily low
4.3°C
Annual rainfall
922mm
Sunshine / day
9.0h
Mean relative humidity
70%
Average peak wind
22.1km/h
Seasonal range
30.7°C
Frost days (< 0 °C)
133 d/yr
Hot days (≥ 30 °C)
30 d/yr
Rainy days (≥ 1 mm)
105 d/yr
Annual snowfall
69.1 cm
Average feels-like high
12.0 °C
Average feels-like low
1.1 °C
Average peak gust
40.4 km/h
Tropical nights (≥ 20 °C)
26 d/yr
Solar radiation
15.3 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.9 °C
since 1940
+0.2 °C per decade · r² = 0.29 · 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
38.4 °C
15 August 1988
Coldest day
-33.7 °C
16 January 2009
Wettest day
110 mm
22 June 1948
Windiest day
72.2 km/h
4 January 1971
Strongest gust
115.2 km/h
5 May 1950
Hottest feels-like
46.0 °C
6 July 1948
Coldest feels-like
-41.0 °C
9 January 1982
Snowiest day
27.4 cm
9 April 1973
Sunniest day
14.8 h
4 July 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 | -0.8 °C | +2.1 °C | 10 mm | -21 mm |
| Feb | -1.1 °C | -0.9 °C | 13 mm | -21 mm |
| Mar | 13.8 °C | +6.9 °C | 118 mm | +48 mm |
| Apr | 16.4 °C | +1.1 °C | 86 mm | -17 mm |
| May | 22.4 °C | +0.9 °C | 80 mm | -48 mm |
| Jun | 28.4 °C | +1.8 °C | 157 mm | +34 mm |
| Jul | 28.6 °C | +0.2 °C | 253 mm | +156 mm |
| Aug | 26.7 °C | -0.8 °C | 53 mm | -45 mm |
| Sep | 26.2 °C | +2.6 °C | 38 mm | -49 mm |
| Oct | 19.7 °C | +2.6 °C | 78 mm | +12 mm |
| Nov | 9.5 °C | +1.6 °C | 45 mm | -6 mm |
| Dec | 0.8 °C | +0.6 °C | 29 mm | -8 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 Ames?
Ames has a hot-summer humid continental climate (Köppen Dfa). Over 1940-2025, the average annual temperature is 9.2 °C and it receives 922 mm of precipitation per year.
What is the hottest day ever recorded in Ames?
The hottest day measured in Ames between 1940 and 2025 was 15 August 1988, reaching 38.4 °C.
What is the coldest day in Ames?
The coldest day measured in Ames between 1940 and 2025 was 16 January 2009, at -33.7 °C.
Does it snow in Ames?
Yes. Ames gets on average 69.1 cm of snow per year and has around 133 frost days.
Has the climate of Ames warmed?
Yes: Ames warmed by +1.9 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Ames?
The wettest day measured in Ames between 1940 and 2025 was 22 June 1948, with 110 mm of rain in 24 hours.
What was the windiest day in Ames?
The windiest day measured in Ames between 1940 and 2025 was 4 January 1971, with winds reaching 72.2 km/h.
What is the warmest month in Ames?
The warmest month in Ames is July (23.4 °C on average); the coldest is January (-7.3 °C).
How much does it rain in Ames?
Ames receives on average 922 mm of precipitation per year, spread over about 105 rainy days.
Is it sunny in Ames?
Ames gets on average 9.0 hours of sunshine per day, roughly 3,285 hours per year over 1940-2025.
What is the biggest single-day snowfall in Ames?
The heaviest 24-hour snowfall measured in Ames between 1940 and 2025 was 9 April 1973, with 27.4 cm.
Are there tropical nights in Ames?
Yes: Ames has on average 26 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Ames?
In Ames, between 1940 and 2025, the highest apparent temperature reached 46.0 °C on 6 July 1948, and the lowest was -41.0 °C on 9 January 1982.
Compare Ames with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Ames