August is one of the warmer months of the year in Philadelphia, with average highs near 29.2°C and lows around 18.3°C (mean 23.8°C). It is a relatively wet time of year, averaging 111 mm of rainfall and 73% relative humidity across the period.
August is one of the warmer months of the year in Philadelphia. Across 45 years of records, the warmest August in Philadelphia was 2022 — when the month averaged 26.6°C — while the coldest was 1994 at 21.3°C. Typical August days reach 29.2°C with nights near 18.3°C. The long-term trend is warming, about 0.4°C per decade.
August is a relatively wet time of year in Philadelphia, averaging 111 mm of rainfall. The wettest August on record was 2011 with 384 mm, while the driest was 2025 at 36 mm.
Relative humidity in Philadelphia during August averages 73%. The most humid August was 2003 at 85%, and the least humid was 1995 at 59%.
August receives about 5.4 kWh/m²/day of solar energy in Philadelphia. The sunniest Augusts were 2016 and 2022 at 6.1 kWh/m²/day, and the cloudiest were 1989, 1990 and 2000 at 4.8.
Average wind speed in Philadelphia during August is 1.5 m/s. The windiest August was 1995 at 1.8 m/s, while the calmest were 1996 and 2009 at 1.2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 22.9°C | 23.3°C | 24.2°C | 23.8°C | 24.7°C | +1.8°C |
| Avg High | 28.6°C | 29.0°C | 29.6°C | 29.0°C | 29.9°C | +1.3°C |
| Avg Low | 17.2°C | 17.7°C | 18.9°C | 18.6°C | 19.3°C | +2.1°C |
| Avg Rain | 90 mm | 118 mm | 105 mm | 129 mm | 112 mm | +22 mm |
August temperatures in Philadelphia have risen by about 1.8°C between 1981–1985 and 2021–2025.
August has ranged from a record low of 6.5°C (1982) to a record high of 39.1°C (2001).
Rainfall in August is a relatively wet time of year, averaging 111 mm, with a wettest year of 384 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.2°C per decade while lows rose 0.5°C per decade, narrowing the gap between day and night.
One of the best times to visit Philadelphia
August is one of the best times to visit Philadelphia. Expect days averaging 29.2°C and nights around 18.3°C (mean 23.8°C) — warmer than Philadelphia's yearly average — with higher rainfall (111 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 | 29.2°C | 23.2°C | 17.1°C | 34.4°C | 11.5°C | 36 mm | 66% | 1.6 m/s | 5.4 |
| 2024 | 29.4°C | 24.1°C | 18.8°C | 36.1°C | 11.8°C | 135 mm | 76% | 1.6 m/s | 5.4 |
| 2023 | 29.4°C | 24.2°C | 18.9°C | 33.3°C | 14.9°C | 83 mm | 71% | 1.6 m/s | 5.3 |
| 2022 🔥 | 32.5°C | 26.6°C | 20.8°C | 37.6°C | 16.3°C | 68 mm | 65% | 1.5 m/s | 6.1 |
| 2021 | 30.2°C | 25.4°C | 20.5°C | 35.7°C | 16.4°C | 147 mm | 78% | 1.4 m/s | 5 |
| 2020 | 28.9°C | 24.4°C | 19.9°C | 33.0°C | 15.1°C | 202 mm | 80% | 1.5 m/s | 5.2 |
| 2019 | 28.4°C | 23.6°C | 18.7°C | 32.1°C | 13.7°C | 79 mm | 79% | 1.3 m/s | 5.5 |
| 2018 | 28.8°C | 24.6°C | 20.3°C | 33.0°C | 14.8°C | 182 mm | 84% | 1.5 m/s | 5.6 |
| 2017 | 27.3°C | 22.4°C | 17.5°C | 31.5°C | 13.3°C | 131 mm | 77% | 1.4 m/s | 5.4 |
| 2016 | 31.6°C | 26.0°C | 20.4°C | 35.6°C | 14.2°C | 52 mm | 69% | 1.5 m/s | 6.1 |
| 2015 | 30.4°C | 24.3°C | 18.1°C | 34.2°C | 14.2°C | 61 mm | 66% | 1.5 m/s | 5.9 |
| 2014 | 27.5°C | 21.9°C | 16.3°C | 31.8°C | 12.1°C | 115 mm | 75% | 1.4 m/s | 5.5 |
| 2013 | 26.5°C | 22.0°C | 17.4°C | 29.9°C | 11.5°C | 123 mm | 81% | 1.4 m/s | 5 |
| 2012 | 29.6°C | 24.4°C | 19.2°C | 33.5°C | 14.3°C | 114 mm | 73% | 1.3 m/s | 5.3 |
| 2011 🌧️ | 28.3°C | 23.3°C | 18.4°C | 33.4°C | 12.3°C | 384 mm | 76% | 1.6 m/s | 5.2 |
| 2010 | 31.1°C | 25.2°C | 19.2°C | 36.5°C | 13.6°C | 53 mm | 66% | 1.6 m/s | 5.3 |
| 2009 | 28.0°C | 23.7°C | 19.5°C | 31.6°C | 14.0°C | 198 mm | 84% | 1.2 m/s | 5.3 |
| 2008 | 29.5°C | 23.3°C | 17.0°C | 32.6°C | 12.9°C | 56 mm | 65% | 1.4 m/s | 5.9 |
| 2007 | 30.4°C | 24.5°C | 18.6°C | 35.0°C | 14.0°C | 102 mm | 72% | 1.5 m/s | 5.2 |
| 2006 | 30.2°C | 24.7°C | 19.2°C | 35.3°C | 12.9°C | 80 mm | 69% | 1.6 m/s | 5.6 |
| 2005 | 31.6°C | 26.1°C | 20.7°C | 36.4°C | 14.9°C | 62 mm | 68% | 1.4 m/s | 5.2 |
| 2004 | 27.4°C | 22.6°C | 17.8°C | 31.6°C | 11.1°C | 120 mm | 82% | 1.5 m/s | 5.1 |
| 2003 | 27.9°C | 23.5°C | 19.2°C | 31.0°C | 11.5°C | 125 mm | 85% | 1.4 m/s | 5.1 |
| 2002 | 32.6°C | 26.2°C | 19.8°C | 38.6°C | 14.5°C | 80 mm | 59% | 1.6 m/s | 5.4 |
| 2001 | 31.7°C | 25.6°C | 19.5°C | 39.1°C | 15.9°C | 95 mm | 67% | 1.5 m/s | 5.4 |
| 2000 | 26.8°C | 22.1°C | 17.5°C | 31.8°C | 10.0°C | 130 mm | 79% | 1.6 m/s | 4.8 |
| 1999 | 30.6°C | 24.6°C | 18.7°C | 37.0°C | 13.4°C | 145 mm | 62% | 1.7 m/s | 5.3 |
| 1998 | 30.4°C | 24.4°C | 18.5°C | 34.6°C | 11.3°C | 69 mm | 68% | 1.6 m/s | 5.7 |
| 1997 | 28.1°C | 22.4°C | 16.7°C | 34.9°C | 12.4°C | 136 mm | 70% | 1.4 m/s | 5.4 |
| 1996 | 26.9°C | 21.9°C | 16.9°C | 30.4°C | 13.7°C | 89 mm | 81% | 1.2 m/s | 5.5 |
| 1995 | 32.2°C | 25.2°C | 18.3°C | 37.0°C | 13.4°C | 44 mm | 59% | 1.8 m/s | 5.7 |
| 1994 ❄️ | 26.5°C | 21.3°C | 16.1°C | 31.6°C | 10.1°C | 158 mm | 79% | 1.5 m/s | 5.2 |
| 1993 | 30.0°C | 24.3°C | 18.6°C | 34.6°C | 14.7°C | 121 mm | 71% | 1.3 m/s | 5.5 |
| 1992 | 27.5°C | 21.9°C | 16.2°C | 31.6°C | 11.1°C | 104 mm | 71% | 1.6 m/s | 5.5 |
| 1991 | 30.1°C | 24.3°C | 18.5°C | 34.7°C | 15.3°C | 125 mm | 70% | 1.6 m/s | 5.6 |
| 1990 | 27.7°C | 22.9°C | 18.0°C | 32.4°C | 13.6°C | 188 mm | 79% | 1.5 m/s | 4.8 |
| 1989 | 26.5°C | 22.1°C | 17.8°C | 30.3°C | 12.2°C | 114 mm | 83% | 1.5 m/s | 4.8 |
| 1988 | 30.8°C | 24.9°C | 19.0°C | 36.8°C | 11.4°C | 92 mm | 67% | 1.7 m/s | 5.3 |
| 1987 | 28.4°C | 22.6°C | 16.8°C | 33.5°C | 10.6°C | 102 mm | 72% | 1.5 m/s | 5.3 |
| 1986 | 28.2°C | 22.4°C | 16.7°C | 32.9°C | 7.2°C | 110 mm | 69% | 1.7 m/s | 5.4 |
| 1985 | 28.5°C | 23.1°C | 17.6°C | 34.9°C | 13.0°C | 93 mm | 70% | 1.4 m/s | 5.4 |
| 1984 | 27.1°C | 22.3°C | 17.4°C | 29.8°C | 9.6°C | 65 mm | 83% | 1.3 m/s | 6 |
| 1983 | 31.0°C | 24.6°C | 18.1°C | 37.0°C | 10.7°C | 73 mm | 67% | 1.5 m/s | — |
| 1982 | 27.9°C | 21.7°C | 15.4°C | 31.8°C | 6.5°C | 74 mm | 67% | 1.5 m/s | — |
| 1981 | 28.9°C | 22.6°C | 16.3°C | 32.6°C | 10.1°C | 89 mm | 66% | 1.5 m/s | — |
Actual recorded August data for each year, 1981–2025 — sourced from NASA POWER.
The average high in August is around 29.2°C with lows near 18.3°C (mean 23.8°C), based on 45 years of NASA POWER data.
August averages 111 mm of rainfall in Philadelphia, a relatively wet time of year. The wettest on record was 384 mm in 2011.
The hottest August reached 39.1°C in 2001. The coldest dipped to 6.5°C in 1982.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average August temperatures have risen by about 1.8°C. Daytime highs moved from 28.7°C to 30.1°C and overnight lows from 17°C to 19.2°C over the same span.
August is one of the warmer months of the year in Philadelphia and a relatively wet time of year, so plan for around 29.2°C daytime highs and 18.3°C at night.
Not quite — August is the 11th coolest month in Philadelphia, averaging 23.8°C.
For August in Philadelphia, pack light layers you can adjust through the day, with typical highs of 29.2°C and lows of 18.3°C. Bring an umbrella or light rain jacket too.
Relative humidity in August averages 73% — moderately humid.
Average wind speed in August is 1.5 m/s. The windiest August on record averaged 1.8 m/s (1995).
The wettest August on record was 2011 with 384 mm. On average, August sees 111 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 Philadelphia 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.
