August is one of the warmer months of the year in Allentown, with average highs near 28.8°C and lows around 16.9°C (mean 22.9°C). It is about average for rainfall, averaging 108 mm of rainfall and 71% relative humidity across the period.
August is one of the warmer months of the year in Allentown. Across 45 years of records, the warmest August in Allentown was 2022 — when the month averaged 25.7°C — while the coldest was 1982 at 20°C. Typical August days reach 28.8°C with nights near 16.9°C. The long-term trend is warming, about 0.4°C per decade.
August is about average for rainfall in Allentown, averaging 108 mm of rainfall. The wettest August on record was 2011 with 298 mm, while the driest was 1995 at 34 mm.
Relative humidity in Allentown during August averages 71%. The most humid August was 2018 at 85%, and the least humid was 2002 at 57%.
August receives about 5.2 kWh/m²/day of solar energy in Allentown. The sunniest Augusts were 2015 and 2022 at 5.8 kWh/m²/day, and the cloudiest were 1989, 1990 and 2000 at 4.7.
Average wind speed in Allentown during August is 0.4 m/s. The windiest Augusts were 2023, 2024 and 2025, among others at 0.4 m/s, while the calmest were 1996, 2003 and 2009 at 0.3 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 22.0°C | 22.6°C | 23.2°C | 23.0°C | 23.7°C | +1.7°C |
| Avg High | 28.1°C | 28.9°C | 29.0°C | 28.7°C | 29.5°C | +1.4°C |
| Avg Low | 15.8°C | 16.3°C | 17.4°C | 17.2°C | 17.9°C | +2.1°C |
| Avg Rain | 90 mm | 102 mm | 107 mm | 120 mm | 124 mm | +34 mm |
August temperatures in Allentown have risen by about 1.8°C between 1981–1985 and 2021–2025.
August has ranged from a record low of 4.6°C (1982) to a record high of 38.5°C (2002).
Rainfall in August is about average for rainfall, averaging 108 mm, with a wettest year of 298 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 Allentown
August is one of the best times to visit Allentown. Expect days averaging 28.8°C and nights around 16.9°C (mean 22.9°C) — warmer than Allentown's yearly average — with higher rainfall (108 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 | 29.1°C | 22.4°C | 15.8°C | 34.8°C | 9.2°C | 44 mm | 63% | 0.4 m/s | 5.4 |
| 2024 | 28.8°C | 23.1°C | 17.4°C | 35.6°C | 10.5°C | 162 mm | 75% | 0.4 m/s | 4.9 |
| 2023 | 28.2°C | 22.8°C | 17.4°C | 32.0°C | 13.0°C | 114 mm | 72% | 0.4 m/s | 5 |
| 2022 🔥 | 32.1°C | 25.7°C | 19.3°C | 37.0°C | 14.2°C | 68 mm | 61% | 0.4 m/s | 5.8 |
| 2021 | 30.0°C | 24.6°C | 19.2°C | 36.3°C | 14.3°C | 179 mm | 76% | 0.4 m/s | 4.8 |
| 2020 | 28.8°C | 23.6°C | 18.4°C | 33.3°C | 13.3°C | 180 mm | 77% | 0.4 m/s | 5.3 |
| 2019 | 28.6°C | 23.0°C | 17.5°C | 33.4°C | 13.1°C | 84 mm | 75% | 0.4 m/s | 5.4 |
| 2018 | 27.8°C | 23.4°C | 19.0°C | 32.6°C | 13.6°C | 195 mm | 85% | 0.4 m/s | 4.9 |
| 2017 | 26.8°C | 21.4°C | 16.0°C | 31.2°C | 10.9°C | 131 mm | 76% | 0.4 m/s | 5.1 |
| 2016 | 30.8°C | 24.8°C | 18.9°C | 34.1°C | 13.1°C | 65 mm | 70% | 0.4 m/s | 5.7 |
| 2015 | 30.2°C | 23.6°C | 17.0°C | 34.6°C | 13.2°C | 73 mm | 62% | 0.4 m/s | 5.8 |
| 2014 | 28.1°C | 21.7°C | 15.4°C | 33.7°C | 10.8°C | 72 mm | 69% | 0.4 m/s | 5.2 |
| 2013 | 27.0°C | 21.7°C | 16.3°C | 31.5°C | 9.9°C | 124 mm | 77% | 0.4 m/s | 4.9 |
| 2012 | 29.5°C | 23.6°C | 17.7°C | 33.4°C | 12.9°C | 94 mm | 68% | 0.4 m/s | 5.4 |
| 2011 🌧️ | 27.6°C | 22.2°C | 16.8°C | 33.2°C | 10.1°C | 298 mm | 78% | 0.4 m/s | 4.9 |
| 2010 | 30.5°C | 24.1°C | 17.7°C | 35.4°C | 12.1°C | 65 mm | 65% | 0.4 m/s | 4.9 |
| 2009 | 27.3°C | 22.7°C | 18.0°C | 32.4°C | 12.0°C | 202 mm | 83% | 0.3 m/s | 5.1 |
| 2008 | 28.6°C | 21.9°C | 15.3°C | 31.4°C | 11.0°C | 58 mm | 66% | 0.4 m/s | 5.7 |
| 2007 | 30.0°C | 23.7°C | 17.4°C | 35.9°C | 12.6°C | 127 mm | 69% | 0.4 m/s | 5 |
| 2006 | 28.2°C | 22.7°C | 17.1°C | 32.5°C | 11.0°C | 95 mm | 74% | 0.4 m/s | 5.4 |
| 2005 | 31.3°C | 25.2°C | 19.2°C | 37.4°C | 14.0°C | 63 mm | 67% | 0.4 m/s | 4.8 |
| 2004 | 26.5°C | 21.3°C | 16.2°C | 30.9°C | 10.0°C | 155 mm | 83% | 0.4 m/s | 4.9 |
| 2003 | 27.5°C | 22.7°C | 18.0°C | 32.7°C | 10.1°C | 132 mm | 83% | 0.3 m/s | 4.8 |
| 2002 | 31.9°C | 25.2°C | 18.5°C | 38.5°C | 13.2°C | 56 mm | 57% | 0.4 m/s | 5.4 |
| 2001 | 31.3°C | 24.7°C | 18.1°C | 38.3°C | 14.6°C | 93 mm | 64% | 0.4 m/s | 5.1 |
| 2000 | 27.2°C | 21.7°C | 16.3°C | 31.5°C | 8.8°C | 88 mm | 75% | 0.4 m/s | 4.7 |
| 1999 | 30.4°C | 23.6°C | 16.9°C | 36.7°C | 11.8°C | 98 mm | 59% | 0.4 m/s | 5.3 |
| 1998 | 29.7°C | 23.4°C | 17.0°C | 32.8°C | 9.9°C | 96 mm | 68% | 0.4 m/s | 5.4 |
| 1997 | 27.7°C | 21.5°C | 15.3°C | 33.5°C | 11.0°C | 127 mm | 67% | 0.4 m/s | 5.2 |
| 1996 | 27.8°C | 21.9°C | 16.1°C | 32.0°C | 11.7°C | 65 mm | 76% | 0.3 m/s | 5.4 |
| 1995 | 32.2°C | 24.6°C | 17.0°C | 36.0°C | 11.9°C | 34 mm | 58% | 0.4 m/s | 5.6 |
| 1994 | 26.1°C | 20.5°C | 14.8°C | 31.4°C | 8.8°C | 165 mm | 79% | 0.4 m/s | 4.9 |
| 1993 | 30.2°C | 23.7°C | 17.2°C | 35.1°C | 11.4°C | 96 mm | 67% | 0.4 m/s | 5.2 |
| 1992 | 27.4°C | 21.1°C | 14.8°C | 33.0°C | 9.7°C | 71 mm | 69% | 0.4 m/s | 5.3 |
| 1991 | 30.2°C | 23.6°C | 17.1°C | 36.1°C | 13.7°C | 109 mm | 66% | 0.4 m/s | 5.4 |
| 1990 | 27.6°C | 22.0°C | 16.4°C | 33.0°C | 12.2°C | 164 mm | 76% | 0.4 m/s | 4.7 |
| 1989 | 26.6°C | 21.5°C | 16.3°C | 30.6°C | 10.6°C | 68 mm | 78% | 0.4 m/s | 4.7 |
| 1988 | 29.8°C | 23.6°C | 17.3°C | 36.3°C | 9.2°C | 97 mm | 68% | 0.4 m/s | 5.1 |
| 1987 | 29.1°C | 22.6°C | 16.0°C | 34.8°C | 9.2°C | 117 mm | 67% | 0.4 m/s | 5 |
| 1986 | 26.3°C | 20.6°C | 14.9°C | 30.4°C | 5.5°C | 136 mm | 74% | 0.4 m/s | 5.3 |
| 1985 | 28.0°C | 22.0°C | 16.0°C | 34.4°C | 11.6°C | 77 mm | 69% | 0.4 m/s | 5.2 |
| 1984 | 26.6°C | 21.4°C | 16.3°C | 30.4°C | 8.1°C | 82 mm | 82% | 0.4 m/s | 5.7 |
| 1983 | 30.9°C | 23.9°C | 16.9°C | 36.2°C | 9.5°C | 74 mm | 64% | 0.4 m/s | — |
| 1982 ❄️ | 26.5°C | 20.0°C | 13.6°C | 31.9°C | 4.6°C | 100 mm | 69% | 0.4 m/s | — |
| 1981 | 28.9°C | 22.0°C | 15.1°C | 32.0°C | 8.9°C | 61 mm | 64% | 0.4 m/s | — |
Actual recorded August data for each year, 1981–2025 — sourced from NASA POWER.
The average high in August is around 28.8°C with lows near 16.9°C (mean 22.9°C), based on 45 years of NASA POWER data.
August averages 108 mm of rainfall in Allentown, about average for rainfall. The wettest on record was 298 mm in 2011.
The hottest August reached 38.5°C in 2002. The coldest dipped to 4.6°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 28.2°C to 29.6°C and overnight lows from 15.6°C to 17.8°C over the same span.
August is one of the warmer months of the year in Allentown and about average for rainfall, so plan for around 28.8°C daytime highs and 16.9°C at night.
Not quite — August is the 11th coolest month in Allentown, averaging 22.9°C.
For August in Allentown, pack light layers you can adjust through the day, with typical highs of 28.8°C and lows of 16.9°C. Bring an umbrella or light rain jacket too.
Relative humidity in August averages 71% — moderately humid.
Average wind speed in August is 0.4 m/s. The windiest August on record averaged 0.4 m/s (1981).
The wettest August on record was 2011 with 298 mm. On average, August sees 108 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 Allentown 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.
