Annual mean
Annual mean of daily highs
Annual mean of daily lows
Alton city, Iowa
Official LSAD Designation: Alton city • Census GEOID: 1901585
• Sioux County
Climate Normals & Weather Observations
30-year climate normals (1991–2020) and weather observations for Alton city.
Reference Weather Station: SIOUX CTR 2 SE, IA US (ID: USC00137700)
• Located 8.6 miles from community center
• Elevation: 414.5 m
| Month | Average High (°F) | Average Low (°F) | Mean Temp (°F) | Precipitation (in) |
|---|---|---|---|---|
| January | 27.4° | 9.4° | 18.4° | 0.67" |
| February | 32.9° | 13.9° | 23.4° | 0.88" |
| March | 46.3° | 25.2° | 35.7° | 1.72" |
| April | 61.2° | 36.1° | 48.7° | 2.98" |
| May | 73.2° | 48.4° | 60.8° | 4.15" |
| June | 82.4° | 58.9° | 70.7° | 4.51" |
| July | 84.8° | 61.8° | 73.3° | 3.45" |
| August | 82.3° | 59.5° | 70.9° | 3.40" |
| September | 77.1° | 51.2° | 64.2° | 3.21" |
| October | 63.6° | 38.6° | 51.1° | 2.46" |
| November | 45.8° | 25.4° | 35.6° | 1.43" |
| December | 31.5° | 14.5° | 23.0° | 0.99" |
Annual Temperature History
2010–2025, completed calendar years only.
NOAA station SIOUX CTR 2 SE, IA US (ID: USC00137700) • 8.6 miles from community center .
This is the same reference station used for monthly normals.
Source: NOAA NCEI Global Summary of the Year.
Annual temperature data table (°F)
| Year | Annual mean (°F) | Annual mean of daily highs (°F) | Annual mean of daily lows (°F) |
|---|---|---|---|
| 2010 | 47.8 | 59.1 | 36.4 |
| 2011 | 48.1 | 59.8 | 36.4 |
| 2012 | 52.8 | 65.9 | 39.7 |
| 2013 | 47.0 | 58.2 | 35.7 |
| 2014 | Unavailable | Unavailable | Unavailable |
| 2015 | 50.1 | 61.6 | 38.5 |
| 2016 | 50.7 | 61.5 | 39.9 |
| 2017 | 49.9 | 61.1 | 38.7 |
| 2018 | 46.8 | 57.1 | 36.5 |
| 2019 | Unavailable | Unavailable | Unavailable |
| 2020 | 48.8 | 59.8 | 37.8 |
| 2021 | 50.4 | 61.6 | 39.2 |
| 2022 | 48.4 | 60.8 | 36.0 |
| 2023 | 49.7 | 60.7 | 38.7 |
| 2024 | 51.5 | 62.7 | 40.3 |
| 2025 | 50.4 | 62.0 | 38.7 |
Source: NOAA NCEI 1991–2020 U.S. Climate Normals, National Weather Service.