Rock Island Weather in August
Average highs run from 90°F on August 1 to 82°F on August 31, and lows from 64°F to 57°F. Normal precipitation for the month is 0.23 in over about 2 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
- 86°F
- Average low
- 61°F
- Precipitation
- 0.23 in
- Record high
- 109°FAug 4, 1961
- Record low
- 42°FAug 23, 1992
- Chance of a freeze
- 0%
- Days of 90°F or more
- 12.5
- Daylight
- 14 h 55 min to 13 h 24 min
- Cloud cover
- 37%
- Humidity
- 51%
- Dew point
- 46°F
- Wind
- 6.3 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 | 90°F | 64°F | 107°F 2009 | 51°F 1987 | 7% | 0% |
| Aug 2 | 90°F | 64°F | 103°F 1961 | 48°F 1964 | 7% | 0% |
| Aug 3 | 89°F | 64°F | 107°F 1961 | 52°F 2002 | 7% | 0% |
| Aug 4 | 89°F | 64°F | 109°F 1961 | 53°F 1962 | 7% | 0% |
| Aug 5 | 89°F | 63°F | 102°F 1997 | 45°F 1969 | 7% | 0% |
| Aug 6 | 89°F | 63°F | 103°F 1972 | 50°F 2002 | 7% | 0% |
| Aug 7 | 89°F | 63°F | 103°F 1972 | 52°F 1984 | 7% | 0% |
| Aug 8 | 89°F | 63°F | 104°F 1971 | 53°F 1970 | 7% | 0% |
| Aug 9 | 88°F | 63°F | 104°F 1971 | 50°F 1995 | 7% | 0% |
| Aug 10 | 88°F | 63°F | 104°F 1971 | 53°F 1964 | 7% | 0% |
| Aug 11 | 88°F | 62°F | 104°F 1971 | 53°F 1966 | 7% | 0% |
| Aug 12 | 88°F | 62°F | 103°F 2015 | 53°F 1991 | 7% | 0% |
| Aug 13 | 87°F | 62°F | 102°F 1977 | 48°F 1995 | 7% | 0% |
| Aug 14 | 87°F | 62°F | 102°F 1992 | 49°F 1982 | 7% | 0% |
| Aug 15 | 87°F | 62°F | 104°F 2023 | 49°F 1960 | 7% | 0% |
| Aug 16 | 87°F | 61°F | 103°F 1967 | 49°F 1995 | 7% | 0% |
| Aug 17 | 86°F | 61°F | 104°F 2008 | 48°F 1998 | 7% | 0% |
| Aug 18 | 86°F | 61°F | 104°F 1967 | 47°F 1995 | 7% | 0% |
| Aug 19 | 86°F | 61°F | 103°F 1967 | 48°F 1973 | 7% | 0% |
| Aug 20 | 86°F | 60°F | 102°F 1977 | 46°F 1968 | 7% | 0% |
| Aug 21 | 85°F | 60°F | 100°F 2005 | 46°F 1960 | 7% | 0% |
| Aug 22 | 85°F | 60°F | 100°F 1961 | 43°F 1960 | 7% | 0% |
| Aug 23 | 85°F | 59°F | 101°F 1961 | 42°F 1992 | 7% | 0% |
| Aug 24 | 84°F | 59°F | 100°F 2025 | 44°F 1992 | 7% | 0% |
| Aug 25 | 84°F | 59°F | 101°F 2025 | 46°F 1992 | 7% | 0% |
| Aug 26 | 84°F | 59°F | 95°F 1984 | 47°F 1976 | 7% | 0% |
| Aug 27 | 83°F | 58°F | 96°F 1972 | 47°F 1960 | 7% | 0% |
| Aug 28 | 83°F | 58°F | 99°F 1972 | 45°F 1980 | 7% | 0% |
| Aug 29 | 83°F | 58°F | 100°F 1998 | 46°F 1980 | 7% | 0% |
| Aug 30 | 83°F | 58°F | 97°F 1967 | 45°F 1965 | 7% | 0% |
| Aug 31 | 82°F | 57°F | 99°F 1967 | 45°F 1999 | 7% | 0% |
Chance of rain
- Chance of a wet day
- Chance of snowfall
Sunrise and sunset
Times for 2026, local time (PDT).
- August 1
- sunrise 5:39 AM, sunset 8:34 PM
- August 31
- sunrise 6:18 AM, sunset 7:42 PM
Other months
Sources
Normals: NOAA NCEI U.S. Climate Normals, 1991-2020, station USW00094239 (Wenatchee Pangborn AP), public domain. Records: NOAA GHCN-Daily, station USW00094239, 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.