ClimateAverages

Sioux City Climate

Iowa, United States of America · population 82,821 · 250 weather stations within 200 km · records 1819 to 2025

Average annual daytime high
15.8°C
Warmest month · July
30.8°C
Typical daytime high
Coldest month · January
-13.8°C
Typical overnight low

Sioux City has an average annual daytime high of 15.8°C, based on the 1951 to 1980 baseline. Its warmest month is July, when highs typically reach 30.8°C, and its coldest is January, with overnight lows near -13.8°C.

Month by month averages

MonthAvg highAvg low
January-2.3°C-13.8°CColdest
February1.7°C-10.2°C
March7.3°C-4.8°C
April16.9°C2.6°C
May23.3°C9.1°C
June28.2°C14.5°C
July30.8°C17.1°CWarmest
August29.6°C16.1°C
September24.8°C10.5°C
October18.8°C3.8°C
November8.9°C-3.6°C
December1.3°C-9.9°C

Temperature range across the year

-16°-4°8°21°33°JanFebMarAprMayJunJulAugSepOctNovDec
Daytime high Overnight low
Hottest year on record
2011
+2.9°C vs. 1951–1980
Coldest year on record
1842
-3.2°C vs. 1951–1980

These figures reflect annual averages, not single-day records. Daily observations are outside this dataset's precision.

Is Sioux City getting hotter?

Since 1900, Sioux City's average temperature has risen by +2.2°C. Compared to the earliest station records that begin in 1819, warming totals +1.8°C.

8.4°9.1°9.8°10.5°11.1°1951–1980 baseline190019251950197520002025

20-year smoothed annual temperature reconstructed from station anomalies. Dashed line: 1951–1980 baseline.

Best time to visit
April to October

Daytime highs sit within a comfortable 15°C to 26°C range.

FAQ

What is the average temperature in Sioux City?

Sioux City's average annual daytime high is 15.8°C, based on the 1951 to 1980 baseline period. The warmest month is July, with highs averaging 30.8°C, and the coldest is January, with lows averaging -13.8°C.

What is the warmest month in Sioux City?

July is the warmest month in Sioux City, with typical daytime highs of 30.8°C.

What is the hottest year on record for Sioux City?

2011 is the hottest year on record for Sioux City, running +2.9°C above the 1951 to 1980 baseline.

Is Sioux City getting hotter?

Yes. Since 1900, Sioux City has warmed by roughly +2.2°C.

When is the best time to visit Sioux City?

April to October typically offers the most comfortable daytime highs, in the 15°C to 26°C range.

Nearby cities

Baseline period 1951 to 1980. Monthly averages are the mean of station observations weighted by proximity. Warming trend is the 20-year smoothed anomaly against that baseline.