Sioux City climate — normals and trends
Sioux City (United States) has a hot-summer humid continental climate (Dfa) under the Köppen-Geiger classification. Its mean annual temperature is 9.3 °C and it receives 787 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 (24.1 °C on average) and the coldest is January (-7.1 °C). Rainfall peaks in May.
Sioux City averages 138 frost days, 40 hot days (≥ 30 °C) and 96 rainy days per year.
Sioux City 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 144 to 132 per year over the period.
The hottest day of the period reached 40.5 °C (on 21 June 1988) and the coldest -35.6 °C (on 15 January 1972).
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
Sioux CityIowa
- coords
- 42.50°, -96.40°
- period
- 1940–2025 · 86 yrs
Mean daily temperature
9.3°C
Average daily high
14.7°C
Average daily low
4.1°C
Annual rainfall
787mm
Sunshine / day
9.3h
Mean relative humidity
69%
Average peak wind
22.7km/h
Seasonal range
31.2°C
Frost days (< 0 °C)
138 d/yr
Hot days (≥ 30 °C)
40 d/yr
Rainy days (≥ 1 mm)
96 d/yr
Annual snowfall
72.9 cm
Average feels-like high
12.3 °C
Average feels-like low
0.8 °C
Average peak gust
41.2 km/h
Tropical nights (≥ 20 °C)
27 d/yr
Solar radiation
15.6 MJ/m²
Has the climate changed?
One stripe per year, 1940 to 2025
+1.7 °C
since 1940
+0.2 °C per decade · r² = 0.26 · 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
40.5 °C
21 June 1988
Coldest day
-35.6 °C
15 January 1972
Wettest day
94 mm
16 October 1968
Windiest day
68.4 km/h
10 January 1975
Strongest gust
122.0 km/h
10 October 1949
Hottest feels-like
46.6 °C
11 July 1954
Coldest feels-like
-40.8 °C
24 December 1983
Snowiest day
29.4 cm
9 November 1977
Sunniest day
15.0 h
13 June 1940
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 | 0.0 °C | +2.2 °C | 4 mm | -20 mm |
| Feb | -0.3 °C | -0.8 °C | 12 mm | -15 mm |
| Mar | 13.5 °C | +6.4 °C | 71 mm | +12 mm |
| Apr | 17.0 °C | +1.6 °C | 60 mm | -27 mm |
| May | 22.6 °C | +1.0 °C | 138 mm | +23 mm |
| Jun | 28.5 °C | +1.5 °C | 106 mm | -6 mm |
| Jul | 28.9 °C | -0.6 °C | 157 mm | +79 mm |
| Aug | 27.1 °C | -1.2 °C | 64 mm | -25 mm |
| Sep | 26.3 °C | +2.3 °C | 46 mm | -28 mm |
| Oct | 20.0 °C | +2.7 °C | 38 mm | -17 mm |
| Nov | 9.6 °C | +1.9 °C | 33 mm | -6 mm |
| Dec | 3.0 °C | +2.7 °C | 22 mm | -7 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 Sioux City?
Sioux City has a hot-summer humid continental climate (Köppen Dfa). Over 1940-2025, the average annual temperature is 9.3 °C and it receives 787 mm of precipitation per year.
What is the hottest day ever recorded in Sioux City?
The hottest day measured in Sioux City between 1940 and 2025 was 21 June 1988, reaching 40.5 °C.
What is the coldest day in Sioux City?
The coldest day measured in Sioux City between 1940 and 2025 was 15 January 1972, at -35.6 °C.
Does it snow in Sioux City?
Yes. Sioux City gets on average 72.9 cm of snow per year and has around 138 frost days.
Has the climate of Sioux City warmed?
Yes: Sioux City warmed by +1.7 °C between 1940 and 2025, a statistically significant trend.
What is the wettest day in Sioux City?
The wettest day measured in Sioux City between 1940 and 2025 was 16 October 1968, with 94 mm of rain in 24 hours.
What was the windiest day in Sioux City?
The windiest day measured in Sioux City between 1940 and 2025 was 10 January 1975, with winds reaching 68.4 km/h.
What is the warmest month in Sioux City?
The warmest month in Sioux City is July (24.1 °C on average); the coldest is January (-7.1 °C).
How much does it rain in Sioux City?
Sioux City receives on average 787 mm of precipitation per year, spread over about 96 rainy days.
Is it sunny in Sioux City?
Sioux City gets on average 9.3 hours of sunshine per day, roughly 3,395 hours per year over 1940-2025.
What is the biggest single-day snowfall in Sioux City?
The heaviest 24-hour snowfall measured in Sioux City between 1940 and 2025 was 9 November 1977, with 29.4 cm.
Are there tropical nights in Sioux City?
Yes: Sioux City has on average 27 tropical nights per year (temperature staying above 20 °C), over 1940-2025.
What was the most extreme apparent temperature in Sioux City?
In Sioux City, between 1940 and 2025, the highest apparent temperature reached 46.6 °C on 11 July 1954, and the lowest was -40.8 °C on 24 December 1983.
Compare Sioux City with another city
Pick a second city: its normals will be set against these, indicator by indicator.
Nearby cities
The climate around Sioux City