August is one of the warmer months of the year in Rockford, with average highs near 27°C and lows around 15.9°C (mean 21.5°C). It is a relatively wet time of year, averaging 107 mm of rainfall and 75% relative humidity across the period.
August is one of the warmer months of the year in Rockford. Across 45 years of records, the warmest August in Rockford was 1988 — when the month averaged 24.8°C — while the coldest were 1986, 1992 and 2004 at 18.5°C. Typical August days reach 27°C with nights near 15.9°C. The long-term August temperature trend is broadly flat.
August is a relatively wet time of year in Rockford, averaging 107 mm of rainfall. The wettest August on record was 2007 with 339 mm, while the driest was 2003 at 32 mm.
Relative humidity in Rockford during August averages 75%. The most humid August was 1993 at 85%, and the least humid was 1988 at 57%.
August receives about 5.3 kWh/m²/day of solar energy in Rockford. The sunniest Augusts were 2002, 2011 and 2020 at 5.9 kWh/m²/day, and the cloudiest was 1987 at 4.6.
Average wind speed in Rockford during August is 2.3 m/s. The windiest August was 1988 at 2.8 m/s, while the calmest were 2020, 2021 and 2025, among others at 2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 21.3°C | 20.9°C | 21.7°C | 21.4°C | 21.9°C | +0.6°C |
| Avg High | 27.2°C | 26.3°C | 27.4°C | 26.6°C | 27.4°C | +0.2°C |
| Avg Low | 15.5°C | 15.5°C | 16.0°C | 16.2°C | 16.4°C | +0.9°C |
| Avg Rain | 121 mm | 102 mm | 117 mm | 94 mm | 99 mm | -22 mm |
August temperatures in Rockford have risen by about 0.6°C between 1981–1985 and 2021–2025.
August has ranged from a record low of 4.1°C (1986) to a record high of 39.6°C (1988).
Rainfall in August is a relatively wet time of year, averaging 107 mm, with a wettest year of 339 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0°C per decade while lows rose 0.2°C per decade, narrowing the gap between day and night.
One of the best times to visit Rockford
August is one of the best times to visit Rockford. Expect days averaging 27°C and nights around 15.9°C (mean 21.5°C) — warmer than Rockford's yearly average — with higher rainfall (107 mm), so conditions are generally comfortable for sightseeing and outdoor plans.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 26.4°C | 21.1°C | 15.8°C | 32.8°C | 9.3°C | 131 mm | 76% | 2 m/s | 5.4 |
| 2024 | 26.8°C | 21.4°C | 16.1°C | 33.2°C | 10.6°C | 73 mm | 77% | 2.2 m/s | 5.5 |
| 2023 | 28.6°C | 22.4°C | 16.1°C | 37.4°C | 9.5°C | 68 mm | 70% | 2.4 m/s | 5.6 |
| 2022 | 27.3°C | 21.8°C | 16.3°C | 33.5°C | 12.7°C | 139 mm | 76% | 2.3 m/s | 5.2 |
| 2021 | 29.4°C | 23.8°C | 18.2°C | 32.3°C | 13.5°C | 114 mm | 73% | 2 m/s | 5.5 |
| 2020 | 26.1°C | 21.1°C | 16.0°C | 30.7°C | 10.9°C | 70 mm | 79% | 2 m/s | 5.9 |
| 2019 | 25.2°C | 20.3°C | 15.4°C | 28.2°C | 11.0°C | 106 mm | 81% | 2 m/s | 5.6 |
| 2018 | 26.9°C | 22.1°C | 17.3°C | 31.1°C | 11.5°C | 137 mm | 81% | 2.1 m/s | 5 |
| 2017 | 24.0°C | 18.9°C | 13.7°C | 27.9°C | 8.3°C | 54 mm | 80% | 2.2 m/s | 5.2 |
| 2016 | 27.5°C | 22.7°C | 18.0°C | 31.4°C | 12.3°C | 131 mm | 80% | 2.1 m/s | 5.5 |
| 2015 | 27.2°C | 21.3°C | 15.5°C | 33.7°C | 10.3°C | 89 mm | 72% | 2.5 m/s | 5.3 |
| 2014 | 26.5°C | 21.4°C | 16.3°C | 30.1°C | 9.4°C | 137 mm | 81% | 2 m/s | 5.2 |
| 2013 | 25.9°C | 20.7°C | 15.4°C | 32.3°C | 10.1°C | 60 mm | 80% | 2.1 m/s | 5.6 |
| 2012 | 29.7°C | 22.9°C | 16.0°C | 35.9°C | 10.9°C | 56 mm | 59% | 2.2 m/s | 5.7 |
| 2011 | 26.5°C | 21.5°C | 16.4°C | 31.2°C | 12.8°C | 93 mm | 78% | 2 m/s | 5.9 |
| 2010 | 27.0°C | 22.4°C | 17.8°C | 31.5°C | 10.2°C | 81 mm | 84% | 2.2 m/s | 5.6 |
| 2009 | 24.2°C | 19.4°C | 14.5°C | 29.8°C | 6.5°C | 146 mm | 82% | 2.7 m/s | 5 |
| 2008 | 25.3°C | 20.0°C | 14.7°C | 28.8°C | 10.9°C | 49 mm | 80% | 2.1 m/s | 5.8 |
| 2007 🌧️ | 27.0°C | 22.4°C | 17.7°C | 32.3°C | 12.2°C | 339 mm | 82% | 2.3 m/s | 4.8 |
| 2006 | 28.8°C | 22.7°C | 16.7°C | 35.9°C | 12.3°C | 108 mm | 69% | 2.4 m/s | 5 |
| 2005 | 30.1°C | 23.5°C | 16.9°C | 36.5°C | 12.0°C | 83 mm | 62% | 2.2 m/s | 5.8 |
| 2004 | 23.6°C | 18.5°C | 13.3°C | 29.3°C | 7.8°C | 91 mm | 77% | 2.5 m/s | 5.1 |
| 2003 | 30.5°C | 24.0°C | 17.6°C | 37.1°C | 14.6°C | 32 mm | 65% | 2.4 m/s | 5.6 |
| 2002 | 28.8°C | 22.4°C | 16.1°C | 34.8°C | 10.6°C | 142 mm | 70% | 2.2 m/s | 5.9 |
| 2001 | 28.4°C | 22.6°C | 16.9°C | 35.2°C | 12.3°C | 109 mm | 71% | 2.3 m/s | 5.5 |
| 2000 | 27.0°C | 21.2°C | 15.4°C | 34.0°C | 11.2°C | 68 mm | 77% | 2.3 m/s | 5.3 |
| 1999 | 25.8°C | 20.3°C | 14.7°C | 31.8°C | 10.6°C | 68 mm | 74% | 2.4 m/s | 5.2 |
| 1998 | 27.1°C | 22.0°C | 17.0°C | 31.5°C | 12.7°C | 139 mm | 78% | 2 m/s | 5.1 |
| 1997 | 26.0°C | 20.1°C | 14.2°C | 32.9°C | 10.3°C | 96 mm | 75% | 2.5 m/s | 4.7 |
| 1996 | 25.8°C | 20.6°C | 15.4°C | 29.7°C | 12.2°C | 82 mm | 78% | 2 m/s | 5.7 |
| 1995 | 28.8°C | 24.0°C | 19.2°C | 33.5°C | 14.8°C | 132 mm | 81% | 2.3 m/s | 4.9 |
| 1994 | 24.4°C | 19.0°C | 13.6°C | 29.4°C | 7.5°C | 148 mm | 79% | 2.4 m/s | 4.9 |
| 1993 | 25.5°C | 21.1°C | 16.6°C | 30.4°C | 10.8°C | 86 mm | 85% | 2.2 m/s | 5 |
| 1992 | 24.5°C | 18.5°C | 12.5°C | 30.0°C | 8.4°C | 82 mm | 72% | 2.3 m/s | 5.4 |
| 1991 | 29.2°C | 22.8°C | 16.5°C | 36.0°C | 12.6°C | 59 mm | 65% | 2.3 m/s | 5.5 |
| 1990 | 26.2°C | 21.0°C | 15.7°C | 31.0°C | 9.4°C | 128 mm | 80% | 2.4 m/s | 5.4 |
| 1989 | 26.4°C | 20.7°C | 14.9°C | 30.5°C | 7.9°C | 164 mm | 76% | 2.2 m/s | 5.2 |
| 1988 🔥 | 31.6°C | 24.8°C | 18.0°C | 39.6°C | 9.0°C | 85 mm | 57% | 2.8 m/s | 5.6 |
| 1987 | 25.4°C | 20.7°C | 15.9°C | 34.0°C | 7.5°C | 236 mm | 78% | 2.5 m/s | 4.6 |
| 1986 ❄️ | 24.3°C | 18.5°C | 12.7°C | 28.8°C | 4.1°C | 80 mm | 73% | 2.4 m/s | 5.2 |
| 1985 | 26.3°C | 20.1°C | 13.8°C | 31.9°C | 9.3°C | 92 mm | 70% | 2.3 m/s | 5.1 |
| 1984 | 29.4°C | 22.8°C | 16.3°C | 36.7°C | 9.8°C | 57 mm | 67% | 2.2 m/s | 5.5 |
| 1983 | 30.0°C | 23.8°C | 17.6°C | 36.3°C | 11.6°C | 88 mm | 71% | 2.2 m/s | — |
| 1982 | 24.9°C | 19.5°C | 14.1°C | 32.0°C | 6.9°C | 81 mm | 77% | 2.3 m/s | — |
| 1981 | 26.6°C | 21.2°C | 15.8°C | 31.3°C | 9.1°C | 203 mm | 77% | 2.2 m/s | — |
Actual recorded August data for each year, 1981–2025 — sourced from NASA POWER.
The average high in August is around 27°C with lows near 15.9°C (mean 21.5°C), based on 45 years of NASA POWER data.
August averages 107 mm of rainfall in Rockford, a relatively wet time of year. The wettest on record was 339 mm in 2007.
The hottest August reached 39.6°C in 1988. The coldest dipped to 4.1°C in 1986.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average August temperatures have risen by about 0.6°C. Daytime highs moved from 27.4°C to 27.7°C and overnight lows from 15.5°C to 16.5°C over the same span.
August is one of the warmer months of the year in Rockford and a relatively wet time of year, so plan for around 27°C daytime highs and 15.9°C at night.
Not quite — August is the 11th coolest month in Rockford, averaging 21.5°C.
For August in Rockford, pack light layers you can adjust through the day, with typical highs of 27°C and lows of 15.9°C. Bring an umbrella or light rain jacket too.
Relative humidity in August averages 75% — moderately humid.
Average wind speed in August is 2.3 m/s. The windiest August on record averaged 2.8 m/s (1988).
The wettest August on record was 2007 with 339 mm. On average, August sees 107 mm.
All figures are derived from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite reanalysis, covering 1981–2025.
Explore how the weather in Rockford behaves each August, based on 45 years of NASA POWER climate data from 1981 to 2025. This page breaks down average temperatures, rainfall, humidity, wind and solar radiation for August specifically, along with year-by-year records and how the month has changed over the decades.
