August is one of the warmer months of the year in Waukegan, with average highs near 27.2°C and lows around 16.7°C (mean 22°C). It is a relatively wet time of year, averaging 106 mm of rainfall and 73% relative humidity across the period.
August is one of the warmer months of the year in Waukegan. Across 45 years of records, the warmest August in Waukegan was 1988 — when the month averaged 24.8°C — while the coldest was 1992 at 19°C. Typical August days reach 27.2°C with nights near 16.7°C. The long-term trend is warming, about 0.2°C per decade.
August is a relatively wet time of year in Waukegan, averaging 106 mm of rainfall. The wettest August on record was 2007 with 324 mm, while the driest was 2003 at 36 mm.
Relative humidity in Waukegan during August averages 73%. The most humid August was 1993 at 84%, and the least humid was 1988 at 59%.
August receives about 5.1 kWh/m²/day of solar energy in Waukegan. The sunniest Augusts were 2002, 2008 and 2020 at 5.7 kWh/m²/day, and the cloudiest was 1987 at 4.4.
Average wind speed in Waukegan during August is 2.5 m/s. The windiest Augusts were 1988 and 2009 at 3 m/s, while the calmest was 2014 at 2.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 21.7°C | 21.5°C | 22.2°C | 22.0°C | 22.6°C | +0.9°C |
| Avg High | 27.3°C | 26.7°C | 27.5°C | 27.1°C | 27.8°C | +0.5°C |
| Avg Low | 16.1°C | 16.4°C | 16.8°C | 17.0°C | 17.3°C | +1.2°C |
| Avg Rain | 121 mm | 102 mm | 115 mm | 92 mm | 98 mm | -23 mm |
August temperatures in Waukegan have risen by about 0.8°C between 1981–1985 and 2021–2025.
August has ranged from a record low of 5.4°C (1986) to a record high of 39.2°C (1988).
Rainfall in August is a relatively wet time of year, averaging 106 mm, with a wettest year of 324 mm.
One of the best times to visit Waukegan
August is one of the best times to visit Waukegan. Expect days averaging 27.2°C and nights around 16.7°C (mean 22°C) — warmer than Waukegan's yearly average — with higher rainfall (106 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 | 26.7°C | 21.7°C | 16.7°C | 33.7°C | 10.5°C | 128 mm | 73% | 2.3 m/s | 5.6 |
| 2024 | 27.7°C | 22.5°C | 17.3°C | 35.1°C | 12.1°C | 72 mm | 72% | 2.5 m/s | 5.4 |
| 2023 | 28.3°C | 22.6°C | 16.9°C | 37.2°C | 11.7°C | 69 mm | 69% | 2.7 m/s | 5.3 |
| 2022 | 27.6°C | 22.3°C | 16.9°C | 33.7°C | 13.7°C | 135 mm | 74% | 2.5 m/s | 5.2 |
| 2021 | 29.6°C | 24.4°C | 19.2°C | 33.0°C | 15.2°C | 114 mm | 72% | 2.2 m/s | 5.6 |
| 2020 | 26.8°C | 21.9°C | 17.1°C | 31.8°C | 11.5°C | 71 mm | 76% | 2.3 m/s | 5.7 |
| 2019 | 25.3°C | 20.7°C | 16.2°C | 28.4°C | 11.9°C | 106 mm | 80% | 2.3 m/s | 5.4 |
| 2018 | 27.7°C | 22.9°C | 18.1°C | 32.8°C | 12.6°C | 134 mm | 78% | 2.4 m/s | 5 |
| 2017 | 24.4°C | 19.5°C | 14.7°C | 29.1°C | 10.5°C | 53 mm | 78% | 2.4 m/s | 5.1 |
| 2016 | 28.3°C | 23.5°C | 18.8°C | 32.9°C | 13.0°C | 127 mm | 77% | 2.2 m/s | 5.3 |
| 2015 | 27.7°C | 22.0°C | 16.4°C | 34.1°C | 11.4°C | 88 mm | 71% | 2.6 m/s | 5 |
| 2014 | 26.6°C | 21.8°C | 16.9°C | 29.6°C | 10.4°C | 139 mm | 79% | 2.1 m/s | 5 |
| 2013 | 26.4°C | 21.3°C | 16.2°C | 33.4°C | 11.2°C | 57 mm | 78% | 2.3 m/s | 5.4 |
| 2012 | 29.4°C | 23.1°C | 16.7°C | 35.8°C | 12.0°C | 58 mm | 61% | 2.4 m/s | 5.3 |
| 2011 | 27.2°C | 22.3°C | 17.3°C | 32.3°C | 13.3°C | 88 mm | 75% | 2.3 m/s | 5.5 |
| 2010 | 27.5°C | 23.0°C | 18.5°C | 31.1°C | 12.5°C | 66 mm | 81% | 2.4 m/s | 5.5 |
| 2009 | 25.0°C | 20.1°C | 15.1°C | 30.1°C | 7.6°C | 141 mm | 79% | 3 m/s | 4.8 |
| 2008 | 26.0°C | 20.9°C | 15.9°C | 31.1°C | 12.3°C | 47 mm | 77% | 2.4 m/s | 5.7 |
| 2007 🌧️ | 27.0°C | 22.6°C | 18.2°C | 33.4°C | 12.6°C | 324 mm | 80% | 2.5 m/s | 4.7 |
| 2006 | 28.7°C | 23.3°C | 17.8°C | 37.1°C | 13.6°C | 105 mm | 69% | 2.7 m/s | 4.9 |
| 2005 | 30.0°C | 24.0°C | 18.0°C | 36.3°C | 13.7°C | 78 mm | 62% | 2.4 m/s | 5.4 |
| 2004 | 24.6°C | 19.4°C | 14.1°C | 30.5°C | 8.9°C | 88 mm | 74% | 2.8 m/s | 4.9 |
| 2003 | 29.5°C | 23.8°C | 18.0°C | 37.5°C | 15.1°C | 36 mm | 68% | 2.6 m/s | 5.4 |
| 2002 | 28.5°C | 22.8°C | 17.0°C | 34.9°C | 11.5°C | 147 mm | 71% | 2.5 m/s | 5.7 |
| 2001 | 28.6°C | 23.1°C | 17.5°C | 36.2°C | 13.4°C | 114 mm | 70% | 2.6 m/s | 5.1 |
| 2000 | 27.4°C | 21.8°C | 16.3°C | 34.3°C | 13.0°C | 67 mm | 74% | 2.6 m/s | 5.3 |
| 1999 | 26.4°C | 21.1°C | 15.9°C | 32.3°C | 12.0°C | 68 mm | 71% | 2.7 m/s | 4.9 |
| 1998 | 27.9°C | 23.0°C | 18.2°C | 32.6°C | 13.6°C | 132 mm | 75% | 2.3 m/s | 5 |
| 1997 | 26.1°C | 20.5°C | 15.0°C | 33.1°C | 11.6°C | 99 mm | 74% | 2.8 m/s | 4.7 |
| 1996 | 26.9°C | 21.6°C | 16.4°C | 30.6°C | 13.2°C | 75 mm | 74% | 2.3 m/s | 5.5 |
| 1995 | 28.9°C | 24.3°C | 19.7°C | 34.8°C | 15.5°C | 145 mm | 80% | 2.4 m/s | 4.5 |
| 1994 | 24.8°C | 19.5°C | 14.3°C | 30.6°C | 9.0°C | 138 mm | 77% | 2.8 m/s | 4.8 |
| 1993 | 25.5°C | 21.3°C | 17.2°C | 30.8°C | 11.6°C | 88 mm | 84% | 2.4 m/s | 4.9 |
| 1992 ❄️ | 24.6°C | 19.0°C | 13.4°C | 30.8°C | 10.3°C | 87 mm | 72% | 2.7 m/s | 4.9 |
| 1991 | 28.8°C | 23.0°C | 17.1°C | 35.6°C | 13.3°C | 62 mm | 65% | 2.6 m/s | 5.3 |
| 1990 | 26.7°C | 21.5°C | 16.3°C | 31.8°C | 10.8°C | 127 mm | 77% | 2.6 m/s | 4.8 |
| 1989 | 26.4°C | 21.0°C | 15.6°C | 30.7°C | 9.1°C | 161 mm | 75% | 2.5 m/s | 5.2 |
| 1988 🔥 | 31.0°C | 24.8°C | 18.6°C | 39.2°C | 10.5°C | 84 mm | 59% | 3 m/s | 4.9 |
| 1987 | 25.6°C | 21.0°C | 16.3°C | 34.3°C | 8.5°C | 244 mm | 77% | 2.8 m/s | 4.4 |
| 1986 | 24.8°C | 19.2°C | 13.7°C | 29.7°C | 5.4°C | 80 mm | 70% | 2.7 m/s | 5 |
| 1985 | 26.4°C | 20.6°C | 14.8°C | 31.8°C | 10.1°C | 97 mm | 69% | 2.5 m/s | 5 |
| 1984 | 29.3°C | 23.1°C | 16.9°C | 36.5°C | 11.1°C | 61 mm | 66% | 2.4 m/s | 5.2 |
| 1983 | 29.9°C | 24.0°C | 18.0°C | 35.8°C | 13.1°C | 92 mm | 70% | 2.4 m/s | — |
| 1982 | 25.5°C | 20.1°C | 14.7°C | 31.7°C | 7.4°C | 81 mm | 73% | 2.5 m/s | — |
| 1981 | 26.6°C | 21.6°C | 16.6°C | 31.6°C | 11.6°C | 189 mm | 76% | 2.4 m/s | — |
Actual recorded August data for each year, 1981–2025 — sourced from NASA POWER.
The average high in August is around 27.2°C with lows near 16.7°C (mean 22°C), based on 45 years of NASA POWER data.
August averages 106 mm of rainfall in Waukegan, a relatively wet time of year. The wettest on record was 324 mm in 2007.
The hottest August reached 39.2°C in 1988. The coldest dipped to 5.4°C in 1986.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average August temperatures have risen by about 0.8°C. Daytime highs moved from 27.5°C to 28°C and overnight lows from 16.2°C to 17.4°C over the same span.
August is one of the warmer months of the year in Waukegan and a relatively wet time of year, so plan for around 27.2°C daytime highs and 16.7°C at night.
Not quite — August is the 11th coolest month in Waukegan, averaging 22°C.
For August in Waukegan, pack light layers you can adjust through the day, with typical highs of 27.2°C and lows of 16.7°C. Bring an umbrella or light rain jacket too.
Relative humidity in August averages 73% — moderately humid.
Average wind speed in August is 2.5 m/s. The windiest August on record averaged 3 m/s (1988).
The wettest August on record was 2007 with 324 mm. On average, August sees 106 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 Waukegan 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.
