Rock Island Weather in August
Average highs run from 84°F on August 1 to 81°F on August 31, and lows from 65°F to 60°F. Normal precipitation for the month is 4.03 in over about 10 wet days.
August day by day
The normal high and low for each date, and the record, in °F.
- Normal low
- Normal high
- Record high
- Record low
August at a glance
- Average high
- 82°F
- Average low
- 63°F
- Precipitation
- 4.03 in
- Record high
- 103°FAug 1, 1987
- Record low
- 40°FAug 28, 1986
- Chance of a freeze
- 0%
- Days of 90°F or more
- 4.3
- Daylight
- 14 h 23 min to 13 h 09 min
- Cloud cover
- 50%
- Humidity
- 71%
- Dew point
- 62°F
- Wind
- 7.8 mph
Every day of the month
A wet day has at least 0.01 inch of precipitation; snow means at least 0.1 inch of snowfall.
| Date | Normal high | Normal low | Record high | Record low | Chance wet | Chance of snow |
|---|---|---|---|---|---|---|
| Aug 1 | 84°F | 65°F | 103°F 1987 | 55°F 1947 | 29% | 0% |
| Aug 2 | 83°F | 65°F | 101°F 1987 | 51°F 1985 | 29% | 0% |
| Aug 3 | 83°F | 65°F | 101°F 1983 | 48°F 1950 | 29% | 0% |
| Aug 4 | 83°F | 65°F | 100°F 1947 | 46°F 1978 | 29% | 0% |
| Aug 5 | 83°F | 64°F | 99°F 1947 | 48°F 1978 | 29% | 0% |
| Aug 6 | 83°F | 64°F | 99°F 1947 | 49°F 1948 | 29% | 0% |
| Aug 7 | 83°F | 64°F | 97°F 1984 | 48°F 1975 | 30% | 0% |
| Aug 8 | 83°F | 64°F | 102°F 1988 | 47°F 1976 | 30% | 0% |
| Aug 9 | 83°F | 64°F | 98°F 2005 | 50°F 1972 | 30% | 0% |
| Aug 10 | 83°F | 64°F | 99°F 1983 | 51°F 2024 | 30% | 0% |
| Aug 11 | 83°F | 64°F | 95°F 1947 | 48°F 1968 | 30% | 0% |
| Aug 12 | 83°F | 64°F | 98°F 1975 | 47°F 1967 | 30% | 0% |
| Aug 13 | 83°F | 64°F | 95°F 1944 | 47°F 2004 | 30% | 0% |
| Aug 14 | 83°F | 64°F | 97°F 1988 | 45°F 1964 | 30% | 0% |
| Aug 15 | 83°F | 64°F | 100°F 1988 | 47°F 1964 | 30% | 0% |
| Aug 16 | 83°F | 63°F | 101°F 1988 | 47°F 1992 | 30% | 0% |
| Aug 17 | 83°F | 63°F | 103°F 1983 | 48°F 1992 | 30% | 0% |
| Aug 18 | 82°F | 63°F | 102°F 1988 | 44°F 1963 | 30% | 0% |
| Aug 19 | 82°F | 63°F | 101°F 1983 | 49°F 1981 | 30% | 0% |
| Aug 20 | 82°F | 63°F | 101°F 1983 | 43°F 1950 | 30% | 0% |
| Aug 21 | 82°F | 63°F | 98°F 1983 | 44°F 1950 | 30% | 0% |
| Aug 22 | 82°F | 63°F | 99°F 1947 | 49°F 2012 | 30% | 0% |
| Aug 23 | 82°F | 62°F | 99°F 1947 | 49°F 1952 | 30% | 0% |
| Aug 24 | 82°F | 62°F | 100°F 2023 | 47°F 1952 | 30% | 0% |
| Aug 25 | 82°F | 62°F | 97°F 2003 | 43°F 1958 | 30% | 0% |
| Aug 26 | 82°F | 62°F | 97°F 2003 | 47°F 1964 | 30% | 0% |
| Aug 27 | 81°F | 61°F | 98°F 2024 | 47°F 1968 | 30% | 0% |
| Aug 28 | 81°F | 61°F | 97°F 2013 | 40°F 1986 | 30% | 0% |
| Aug 29 | 81°F | 61°F | 97°F 1984 | 41°F 1986 | 30% | 0% |
| Aug 30 | 81°F | 61°F | 98°F 1947 | 46°F 1946 | 30% | 0% |
| Aug 31 | 81°F | 60°F | 100°F 1953 | 45°F 1967 | 30% | 0% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (CDT).
- August 1
- sunrise 5:57 AM, sunset 8:20 PM
- August 31
- sunrise 6:28 AM, sunset 7:37 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USC00117391 (Rock Island L&d 15), public domain. Records: NOAA GHCN-Daily, station USW00014923, 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.