Waterloo Weather in September
Average highs run from 91°F on September 1 to 85°F on September 30, and lows from 58°F to 54°F. Normal precipitation for the month is 0.10 in over about 1 wet days.
September day by day
The normal high and low for each date, and the record, in °F.
- Normal low
- Normal high
- Record high
- Record low
September at a glance
- Average high
- 89°F
- Average low
- 56°F
- Precipitation
- 0.10 in
- Record high
- 115°FSep 6, 2022
- Record low
- 42°FSep 30, 1950
- Chance of a freeze
- 0%
- Days of 90°F or more
- 13.9
- Daylight
- 12 h 59 min to 11 h 49 min
- Cloud cover
- 20%
- Humidity
- 48%
- Dew point
- 46°F
- Wind
- 7.2 mph
Every day of the month
A wet day has at least 0.01 inch of precipitation.
| Date | Normal high | Normal low | Record high | Record low | Chance wet |
|---|---|---|---|---|---|
| Sep 1 | 91°F | 58°F | 109°F 2017 | 48°F 1964 | 2% |
| Sep 2 | 91°F | 58°F | 110°F 2017 | 49°F 1951 | 2% |
| Sep 3 | 91°F | 57°F | 109°F 2017 | 50°F 1951 | 2% |
| Sep 4 | 91°F | 57°F | 105°F 1988 | 49°F 2000 | 2% |
| Sep 5 | 91°F | 57°F | 112°F 2022 | 50°F 2000 | 2% |
| Sep 6 | 91°F | 57°F | 115°F 2022 | 49°F 1951 | 2% |
| Sep 7 | 90°F | 57°F | 111°F 2020 | 49°F 2002 | 2% |
| Sep 8 | 90°F | 57°F | 112°F 2022 | 48°F 2002 | 2% |
| Sep 9 | 90°F | 57°F | 106°F 2015 | 49°F 1964 | 2% |
| Sep 10 | 90°F | 57°F | 108°F 2015 | 47°F 1985 | 2% |
| Sep 11 | 90°F | 57°F | 103°F 1979 | 48°F 1952 | 2% |
| Sep 12 | 90°F | 57°F | 108°F 1979 | 48°F 1985 | 2% |
| Sep 13 | 89°F | 57°F | 105°F 1971 | 46°F 2016 | 2% |
| Sep 14 | 89°F | 57°F | 104°F 1971 | 48°F 1980 | 3% |
| Sep 15 | 89°F | 56°F | 106°F 1979 | 48°F 2010 | 3% |
| Sep 16 | 89°F | 56°F | 105°F 1979 | 48°F 1980 | 3% |
| Sep 17 | 89°F | 56°F | 100°F 1984 | 49°F 2006 | 3% |
| Sep 18 | 88°F | 56°F | 102°F 2000 | 45°F 1965 | 3% |
| Sep 19 | 88°F | 56°F | 102°F 2000 | 46°F 1965 | 3% |
| Sep 20 | 88°F | 56°F | 101°F 2000 | 46°F 1978 | 4% |
| Sep 21 | 88°F | 56°F | 102°F 2015 | 47°F 1960 | 4% |
| Sep 22 | 87°F | 55°F | 102°F 1949 | 46°F 2017 | 4% |
| Sep 23 | 87°F | 55°F | 101°F 2002 | 45°F 1954 | 4% |
| Sep 24 | 87°F | 55°F | 102°F 2024 | 46°F 2017 | 4% |
| Sep 25 | 87°F | 55°F | 100°F 1952 | 47°F 1955 | 5% |
| Sep 26 | 86°F | 55°F | 100°F 1952 | 47°F 1955 | 5% |
| Sep 27 | 86°F | 55°F | 100°F 2009 | 47°F 1955 | 5% |
| Sep 28 | 86°F | 54°F | 102°F 2010 | 45°F 1986 | 5% |
| Sep 29 | 86°F | 54°F | 102°F 2010 | 45°F 1955 | 5% |
| Sep 30 | 85°F | 54°F | 100°F 2020 | 42°F 1950 | 6% |
Chance of rain
- Chance of a wet day
Sunrise and sunset
Times for 2026, local time (PDT).
- September 1
- sunrise 6:35 AM, sunset 7:34 PM
- September 30
- sunrise 7:00 AM, sunset 6:49 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00045032 (Lodi), public domain. Records: NOAA GHCN-Daily, station USW00023237, every year on file, quality-flagged values removed. Cloud, humidity, wind and sunshine: NASA POWER (MERRA-2, CERES and GEWEX SRB), 1991-2020. The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center's Prediction Of Worldwide Energy Resources (POWER) project funded through the NASA Earth Science Division: POWER Daily API v2, accessed 2026-09-24. Sun and moon: computed with the NOAA solar equations and Meeus.