August is one of the warmer months of the year in Duluth, with average highs near 32.2°C and lows around 20.3°C (mean 26.3°C). It is about average for rainfall, averaging 105 mm of rainfall and 70% relative humidity across the period.
August is one of the warmer months of the year in Duluth. Across 45 years of records, the warmest August in Duluth was 2007 — when the month averaged 29.7°C — while the coldest was 1994 at 23.6°C. Typical August days reach 32.2°C with nights near 20.3°C. The long-term trend is warming, about 0.3°C per decade.
August is about average for rainfall in Duluth, averaging 105 mm of rainfall. The wettest August on record was 1992 with 188 mm, while the driest was 2011 at 42 mm.
Relative humidity in Duluth during August averages 70%. The most humid August was 2013 at 83%, and the least humid was 1999 at 56%.
August receives about 5.5 kWh/m²/day of solar energy in Duluth. The sunniest August was 2024 at 6.6 kWh/m²/day, and the cloudiest was 1992 at 4.7.
Average wind speed in Duluth during August is 0.9 m/s. The windiest Augusts were 1995 and 2008 at 1.1 m/s, while the calmest were 1990, 1996 and 2003 at 0.7 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 25.8°C | 25.9°C | 26.6°C | 26.6°C | 26.6°C | +0.8°C |
| Avg High | 31.6°C | 31.8°C | 32.7°C | 32.4°C | 32.6°C | +1°C |
| Avg Low | 20.0°C | 20.0°C | 20.5°C | 20.7°C | 20.5°C | +0.5°C |
| Avg Rain | 94 mm | 111 mm | 100 mm | 100 mm | 131 mm | +37 mm |
August temperatures in Duluth have risen by about 1.1°C between 1981–1985 and 2021–2025.
August has ranged from a record low of 11.9°C (1992) to a record high of 41°C (1995).
Rainfall in August is about average for rainfall, averaging 105 mm, with a wettest year of 188 mm.
One of the best times to visit Duluth
August is one of the best times to visit Duluth. Expect days averaging 32.2°C and nights around 20.3°C (mean 26.3°C) — warmer than Duluth's yearly average — with higher rainfall (105 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 | 31.0°C | 25.3°C | 19.7°C | 36.0°C | 13.2°C | 115 mm | 73% | 0.9 m/s | 5.2 |
| 2024 | 34.5°C | 27.4°C | 20.2°C | 37.7°C | 15.3°C | 55 mm | 63% | 0.9 m/s | 6.6 |
| 2023 | 34.0°C | 27.5°C | 20.9°C | 38.6°C | 17.3°C | 155 mm | 70% | 0.9 m/s | 5.8 |
| 2022 | 31.9°C | 26.2°C | 20.6°C | 34.8°C | 18.0°C | 115 mm | 73% | 0.8 m/s | 5.3 |
| 2021 | 31.8°C | 26.3°C | 20.8°C | 36.0°C | 17.6°C | 185 mm | 74% | 0.8 m/s | 5.4 |
| 2020 | 32.4°C | 26.7°C | 20.9°C | 36.5°C | 17.3°C | 162 mm | 73% | 0.8 m/s | 5.3 |
| 2019 | 34.3°C | 27.7°C | 21.1°C | 37.9°C | 16.7°C | 84 mm | 65% | 0.8 m/s | 6.1 |
| 2018 | 30.4°C | 25.3°C | 20.2°C | 34.0°C | 15.2°C | 124 mm | 77% | 0.8 m/s | 5.7 |
| 2017 | 31.4°C | 25.8°C | 20.1°C | 35.7°C | 17.8°C | 111 mm | 70% | 0.9 m/s | 5.5 |
| 2016 | 34.3°C | 28.2°C | 22.1°C | 37.1°C | 19.7°C | 80 mm | 67% | 0.9 m/s | 5.8 |
| 2015 | 32.1°C | 26.3°C | 20.4°C | 37.4°C | 13.5°C | 137 mm | 70% | 0.9 m/s | 5.6 |
| 2014 | 32.9°C | 26.3°C | 19.8°C | 36.5°C | 15.6°C | 85 mm | 66% | 0.8 m/s | 5.8 |
| 2013 | 28.7°C | 24.3°C | 19.8°C | 31.8°C | 15.3°C | 127 mm | 83% | 0.8 m/s | 4.9 |
| 2012 | 31.8°C | 25.8°C | 19.9°C | 37.3°C | 14.9°C | 96 mm | 71% | 0.8 m/s | 5.4 |
| 2011 | 35.0°C | 28.2°C | 21.4°C | 37.6°C | 17.4°C | 42 mm | 61% | 0.9 m/s | 6.3 |
| 2010 | 33.6°C | 28.0°C | 22.4°C | 37.6°C | 17.9°C | 109 mm | 73% | 0.8 m/s | 5.6 |
| 2009 | 31.7°C | 25.7°C | 19.8°C | 36.2°C | 15.7°C | 128 mm | 73% | 0.8 m/s | 5.4 |
| 2008 | 32.2°C | 26.1°C | 19.9°C | 37.1°C | 16.2°C | 132 mm | 67% | 1.1 m/s | 5.6 |
| 2007 🔥 | 36.7°C | 29.7°C | 22.8°C | 40.4°C | 20.5°C | 68 mm | 59% | 0.8 m/s | 5.9 |
| 2006 | 34.6°C | 28.3°C | 21.9°C | 38.5°C | 18.4°C | 105 mm | 67% | 0.8 m/s | 5.4 |
| 2005 | 30.6°C | 25.7°C | 20.8°C | 34.6°C | 17.5°C | 145 mm | 80% | 0.8 m/s | 5.3 |
| 2004 | 31.4°C | 25.0°C | 18.5°C | 36.0°C | 12.3°C | 86 mm | 68% | 0.8 m/s | 5.6 |
| 2003 | 30.1°C | 25.4°C | 20.8°C | 32.4°C | 18.3°C | 91 mm | 82% | 0.7 m/s | 5.4 |
| 2002 | 34.1°C | 27.3°C | 20.4°C | 37.9°C | 17.3°C | 52 mm | 60% | 0.9 m/s | 5.7 |
| 2001 | 32.0°C | 26.1°C | 20.2°C | 35.2°C | 15.3°C | 65 mm | 69% | 0.8 m/s | 5.2 |
| 2000 | 33.3°C | 26.6°C | 19.8°C | 39.2°C | 15.4°C | 130 mm | 63% | 0.9 m/s | 5.6 |
| 1999 | 35.7°C | 27.9°C | 20.2°C | 39.6°C | 15.6°C | 54 mm | 56% | 0.9 m/s | 6.3 |
| 1998 | 32.5°C | 26.0°C | 19.4°C | 36.0°C | 14.9°C | 117 mm | 65% | 0.8 m/s | 5.8 |
| 1997 | 30.9°C | 25.0°C | 19.0°C | 35.1°C | 13.1°C | 43 mm | 70% | 0.9 m/s | 5.7 |
| 1996 | 32.0°C | 26.0°C | 20.0°C | 34.3°C | 17.3°C | 110 mm | 70% | 0.7 m/s | 5.4 |
| 1995 | 33.7°C | 27.8°C | 21.9°C | 41.0°C | 19.1°C | 156 mm | 69% | 1.1 m/s | 5.1 |
| 1994 ❄️ | 28.4°C | 23.6°C | 18.9°C | 31.5°C | 15.0°C | 137 mm | 80% | 0.8 m/s | 5.2 |
| 1993 | 33.0°C | 27.0°C | 20.9°C | 37.3°C | 17.5°C | 74 mm | 66% | 0.9 m/s | 5.2 |
| 1992 🌧️ | 29.1°C | 23.9°C | 18.7°C | 34.6°C | 11.9°C | 188 mm | 75% | 0.9 m/s | 4.7 |
| 1991 | 28.6°C | 24.1°C | 19.6°C | 32.8°C | 14.1°C | 135 mm | 82% | 0.8 m/s | 5.2 |
| 1990 | 33.7°C | 27.3°C | 21.0°C | 37.4°C | 17.2°C | 99 mm | 64% | 0.7 m/s | 5.5 |
| 1989 | 29.0°C | 24.1°C | 19.3°C | 32.1°C | 13.5°C | 75 mm | 80% | 0.8 m/s | 5.5 |
| 1988 | 33.2°C | 27.2°C | 21.1°C | 37.5°C | 16.1°C | 100 mm | 68% | 0.9 m/s | 5.1 |
| 1987 | 34.5°C | 27.9°C | 21.4°C | 37.8°C | 17.9°C | 66 mm | 63% | 0.9 m/s | 5.1 |
| 1986 | 31.7°C | 25.9°C | 20.0°C | 38.1°C | 12.6°C | 125 mm | 68% | 1 m/s | 5 |
| 1985 | 29.9°C | 24.6°C | 19.2°C | 33.9°C | 14.9°C | 124 mm | 76% | 1 m/s | 4.8 |
| 1984 | 28.7°C | 23.9°C | 19.2°C | 31.2°C | 15.1°C | 97 mm | 82% | 0.8 m/s | 5 |
| 1983 | 34.9°C | 28.2°C | 21.5°C | 40.8°C | 16.6°C | 55 mm | 60% | 0.8 m/s | — |
| 1982 | 30.4°C | 24.8°C | 19.1°C | 34.4°C | 15.8°C | 108 mm | 75% | 0.9 m/s | — |
| 1981 | 32.0°C | 25.7°C | 19.4°C | 37.5°C | 16.2°C | 100 mm | 67% | 0.8 m/s | — |
Actual recorded August data for each year, 1981–2025 — sourced from NASA POWER.
The average high in August is around 32.2°C with lows near 20.3°C (mean 26.3°C), based on 45 years of NASA POWER data.
August averages 105 mm of rainfall in Duluth, about average for rainfall. The wettest on record was 188 mm in 1992.
The hottest August reached 41°C in 1995. The coldest dipped to 11.9°C in 1992.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average August temperatures have risen by about 1.1°C. Daytime highs moved from 31.2°C to 32.6°C and overnight lows from 19.7°C to 20.4°C over the same span.
August is one of the warmer months of the year in Duluth and about average for rainfall, so plan for around 32.2°C daytime highs and 20.3°C at night.
Not quite — August is the 11th coolest month in Duluth, averaging 26.3°C.
For August in Duluth, pack light, breathable clothing and sun protection, with typical highs of 32.2°C and lows of 20.3°C. Bring an umbrella or light rain jacket too.
Relative humidity in August averages 70% — moderately humid.
Average wind speed in August is 0.9 m/s. The windiest August on record averaged 1.1 m/s (1995).
The wettest August on record was 1992 with 188 mm. On average, August sees 105 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 Duluth 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.
