May is one of the warmer months of the year in West Chester, with average highs near 21.8°C and lows around 10.2°C (mean 16°C). It is about average for rainfall, averaging 105 mm of rainfall and 78% relative humidity across the period.
May is one of the warmer months of the year in West Chester. Across 45 years of records, the warmest May in West Chester was 2004 — when the month averaged 19.1°C — while the coldest was 1997 at 13.4°C. Typical May days reach 21.8°C with nights near 10.2°C. The long-term trend is warming, about 0.4°C per decade.
May is about average for rainfall in West Chester, averaging 105 mm of rainfall. The wettest May on record was 1989 with 216 mm, while the driest was 2023 at 10 mm.
Relative humidity in West Chester during May averages 78%. The most humid May was 2003 at 84%, and the least humid was 2023 at 70%.
May receives about 5.6 kWh/m²/day of solar energy in West Chester. The sunniest May was 2007 at 6.8 kWh/m²/day, and the cloudiest was 2003 at 3.7.
Average wind speed in West Chester during May is 0.5 m/s. The windiest May was 1997 at 0.6 m/s, while the calmest were 2018, 2023 and 2024, among others at 0.4 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 15.4°C | 15.3°C | 15.9°C | 17.2°C | 16.3°C | +0.9°C |
| Avg High | 21.3°C | 21.3°C | 21.8°C | 22.8°C | 22.0°C | +0.7°C |
| Avg Low | 9.5°C | 9.3°C | 10.1°C | 11.7°C | 10.5°C | +1°C |
| Avg Rain | 130 mm | 97 mm | 91 mm | 108 mm | 96 mm | -33 mm |
May temperatures in West Chester have risen by about 1.3°C between 1981–1985 and 2021–2025.
May has ranged from a record low of -0.2°C (2020) to a record high of 34°C (2011).
Rainfall in May is about average for rainfall, averaging 105 mm, with a wettest year of 216 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.3°C per decade while lows rose 0.5°C per decade, narrowing the gap between day and night.
A good time to visit West Chester
May is a good time to visit West Chester, with days averaging 21.8°C and nights around 10.2°C (mean 16°C, warmer than West Chester's yearly average) and higher rainfall. June and August are marginally more temperate, but May still suits most travellers.
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall | Humidity | Wind | Solar |
|---|---|---|---|---|---|---|---|---|---|
| 2025 | 22.3°C | 17.0°C | 11.7°C | 27.9°C | 6.4°C | 196 mm | 78% | 0.5 m/s | 5.1 |
| 2024 | 23.1°C | 18.0°C | 12.9°C | 29.3°C | 5.5°C | 75 mm | 82% | 0.4 m/s | 5 |
| 2023 | 22.0°C | 15.4°C | 8.8°C | 28.1°C | 2.7°C | 10 mm | 70% | 0.4 m/s | 6.4 |
| 2022 | 22.8°C | 17.1°C | 11.4°C | 32.0°C | 5.2°C | 132 mm | 79% | 0.5 m/s | 5.4 |
| 2021 | 21.7°C | 15.7°C | 9.8°C | 30.4°C | 3.2°C | 98 mm | 74% | 0.5 m/s | 5.8 |
| 2020 | 19.9°C | 14.3°C | 8.7°C | 27.5°C | -0.2°C | 67 mm | 76% | 0.5 m/s | 5.7 |
| 2019 | 22.6°C | 17.4°C | 12.2°C | 28.6°C | 5.0°C | 168 mm | 82% | 0.5 m/s | 5.4 |
| 2018 | 24.5°C | 18.9°C | 13.3°C | 29.9°C | 4.4°C | 149 mm | 82% | 0.4 m/s | 5.1 |
| 2017 | 21.0°C | 15.6°C | 10.2°C | 31.5°C | 3.4°C | 135 mm | 77% | 0.5 m/s | 5.1 |
| 2016 | 20.4°C | 15.3°C | 10.2°C | 30.0°C | 2.4°C | 135 mm | 81% | 0.4 m/s | 4.7 |
| 2015 | 24.8°C | 18.7°C | 12.6°C | 30.5°C | 6.4°C | 39 mm | 76% | 0.4 m/s | 6.3 |
| 2014 | 21.9°C | 16.2°C | 10.4°C | 27.4°C | 5.2°C | 100 mm | 80% | 0.4 m/s | 5.4 |
| 2013 | 21.7°C | 16.0°C | 10.3°C | 31.8°C | 1.1°C | 77 mm | 78% | 0.5 m/s | 5.9 |
| 2012 | 24.4°C | 18.9°C | 13.3°C | 32.5°C | 6.3°C | 105 mm | 79% | 0.4 m/s | 5.5 |
| 2011 | 23.0°C | 17.8°C | 12.6°C | 34.0°C | 5.0°C | 92 mm | 82% | 0.4 m/s | 5.6 |
| 2010 | 23.3°C | 17.4°C | 11.6°C | 31.2°C | 1.3°C | 81 mm | 77% | 0.5 m/s | 5.9 |
| 2009 | 21.8°C | 16.4°C | 11.1°C | 27.6°C | 3.3°C | 133 mm | 79% | 0.4 m/s | 5 |
| 2008 | 20.4°C | 14.5°C | 8.6°C | 27.4°C | 2.3°C | 119 mm | 78% | 0.5 m/s | 5.4 |
| 2007 | 23.2°C | 16.8°C | 10.4°C | 30.2°C | 2.5°C | 48 mm | 75% | 0.4 m/s | 6.8 |
| 2006 | 22.5°C | 16.3°C | 10.1°C | 32.8°C | 4.3°C | 57 mm | 72% | 0.5 m/s | 6.3 |
| 2005 | 19.4°C | 13.5°C | 7.7°C | 25.4°C | 1.3°C | 40 mm | 77% | 0.5 m/s | 5.7 |
| 2004 🔥 | 24.5°C | 19.1°C | 13.7°C | 29.5°C | 4.4°C | 103 mm | 81% | 0.4 m/s | 5.8 |
| 2003 | 19.2°C | 14.2°C | 9.3°C | 26.0°C | 3.6°C | 115 mm | 84% | 0.4 m/s | 3.7 |
| 2002 | 22.4°C | 15.7°C | 9.0°C | 30.2°C | 1.8°C | 107 mm | 71% | 0.5 m/s | 6.4 |
| 2001 | 22.8°C | 16.4°C | 10.0°C | 30.9°C | 2.5°C | 97 mm | 74% | 0.4 m/s | 5.8 |
| 2000 | 22.2°C | 16.4°C | 10.7°C | 31.7°C | 2.7°C | 95 mm | 79% | 0.4 m/s | 5.5 |
| 1999 | 23.0°C | 16.3°C | 9.6°C | 32.3°C | 3.7°C | 64 mm | 72% | 0.5 m/s | 5.9 |
| 1998 | 22.6°C | 17.2°C | 11.8°C | 33.1°C | 3.9°C | 136 mm | 82% | 0.4 m/s | 5.6 |
| 1997 ❄️ | 19.5°C | 13.4°C | 7.3°C | 28.0°C | 1.3°C | 79 mm | 73% | 0.6 m/s | 6 |
| 1996 | 19.8°C | 14.2°C | 8.6°C | 30.1°C | 2.1°C | 91 mm | 80% | 0.4 m/s | 5.3 |
| 1995 | 21.1°C | 15.1°C | 9.1°C | 28.1°C | 2.5°C | 93 mm | 76% | 0.5 m/s | 5.3 |
| 1994 | 19.9°C | 13.7°C | 7.5°C | 28.8°C | 2.9°C | 92 mm | 77% | 0.5 m/s | 6 |
| 1993 | 21.9°C | 16.0°C | 10.1°C | 27.9°C | 5.0°C | 56 mm | 78% | 0.4 m/s | 5.8 |
| 1992 | 20.2°C | 14.0°C | 7.9°C | 30.2°C | 1.7°C | 113 mm | 76% | 0.5 m/s | 5.6 |
| 1991 | 24.8°C | 18.6°C | 12.4°C | 31.4°C | 4.8°C | 64 mm | 78% | 0.4 m/s | 6.5 |
| 1990 | 19.7°C | 14.2°C | 8.7°C | 25.8°C | 3.8°C | 181 mm | 78% | 0.5 m/s | 5.1 |
| 1989 🌧️ | 20.1°C | 14.9°C | 9.6°C | 28.1°C | 4.1°C | 216 mm | 82% | 0.5 m/s | 4.8 |
| 1988 | 21.4°C | 15.6°C | 9.9°C | 29.3°C | 2.6°C | 151 mm | 82% | 0.4 m/s | 5.3 |
| 1987 | 21.3°C | 15.4°C | 9.4°C | 31.1°C | 2.0°C | 83 mm | 81% | 0.4 m/s | 5.6 |
| 1986 | 22.6°C | 16.3°C | 10.0°C | 30.2°C | 0.5°C | 39 mm | 76% | 0.4 m/s | 6.4 |
| 1985 | 22.6°C | 16.4°C | 10.3°C | 28.3°C | 2.0°C | 140 mm | 74% | 0.5 m/s | 5.8 |
| 1984 | 19.6°C | 14.3°C | 9.0°C | 26.8°C | 2.7°C | 177 mm | 82% | 0.5 m/s | 4.4 |
| 1983 | 20.0°C | 14.2°C | 8.5°C | 25.2°C | 0.8°C | 149 mm | 81% | 0.5 m/s | — |
| 1982 | 22.4°C | 16.4°C | 10.5°C | 27.6°C | 5.1°C | 98 mm | 79% | 0.4 m/s | — |
| 1981 | 21.9°C | 15.2°C | 8.6°C | 28.6°C | 1.4°C | 112 mm | 74% | 0.5 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 21.8°C with lows near 10.2°C (mean 16°C), based on 45 years of NASA POWER data.
May averages 105 mm of rainfall in West Chester, about average for rainfall. The wettest on record was 216 mm in 1989.
The hottest May reached 34°C in 2011. The coldest dipped to -0.2°C in 2020.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 1.3°C. Daytime highs moved from 21.3°C to 22.4°C and overnight lows from 9.4°C to 10.9°C over the same span.
May is one of the warmer months of the year in West Chester and about average for rainfall, so plan for around 21.8°C daytime highs and 10.2°C at night.
Not quite — May is the 8th coolest month in West Chester, averaging 16°C.
For May in West Chester, pack light layers you can adjust through the day, with typical highs of 21.8°C and lows of 10.2°C. Bring an umbrella or light rain jacket too.
Relative humidity in May averages 78% — quite humid.
Average wind speed in May is 0.5 m/s. The windiest May on record averaged 0.6 m/s (1997).
The wettest May on record was 1989 with 216 mm. On average, May 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 West Chester behaves each May, 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 May specifically, along with year-by-year records and how the month has changed over the decades.
