May is one of the warmer months of the year in Mechanicsburg, with average highs near 21.6°C and lows around 10.1°C (mean 15.9°C). It is a relatively wet time of year, averaging 108 mm of rainfall and 78% relative humidity across the period.
May is one of the warmer months of the year in Mechanicsburg. Across 45 years of records, the warmest May in Mechanicsburg was 2018 — when the month averaged 19.2°C — while the coldest was 1997 at 13.1°C. Typical May days reach 21.6°C with nights near 10.1°C. The long-term trend is warming, about 0.5°C per decade.
May is a relatively wet time of year in Mechanicsburg, averaging 108 mm of rainfall. The wettest May on record was 1989 with 228 mm, while the driest was 2023 at 14 mm.
Relative humidity in Mechanicsburg during May averages 78%. The most humid May was 2003 at 84%, and the least humid was 2023 at 68%.
May receives about 5.3 kWh/m²/day of solar energy in Mechanicsburg. The sunniest May was 2007 at 6.7 kWh/m²/day, and the cloudiest was 2003 at 3.9.
Average wind speed in Mechanicsburg during May is 1.2 m/s. The windiest May was 1997 at 1.6 m/s, while the calmest was 2023 at 1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 15.2°C | 15.1°C | 15.7°C | 17.1°C | 16.1°C | +0.9°C |
| Avg High | 21.0°C | 21.0°C | 21.5°C | 22.6°C | 21.8°C | +0.8°C |
| Avg Low | 9.4°C | 9.2°C | 9.9°C | 11.7°C | 10.4°C | +1°C |
| Avg Rain | 126 mm | 94 mm | 97 mm | 117 mm | 107 mm | -19 mm |
May temperatures in Mechanicsburg have risen by about 1.4°C between 1981–1985 and 2021–2025.
May has ranged from a record low of -1.8°C (2020) to a record high of 32.3°C (2011).
Rainfall in May is a relatively wet time of year, averaging 108 mm, with a wettest year of 228 mm.
A good time to visit Mechanicsburg
May is a good time to visit Mechanicsburg, with days averaging 21.6°C and nights around 10.1°C (mean 15.9°C, warmer than Mechanicsburg'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 | 21.9°C | 16.6°C | 11.4°C | 28.6°C | 5.5°C | 220 mm | 78% | 1.3 m/s | 4.6 |
| 2024 | 23.0°C | 18.0°C | 13.0°C | 29.1°C | 6.3°C | 107 mm | 82% | 1.1 m/s | 5.1 |
| 2023 | 21.9°C | 15.2°C | 8.6°C | 28.5°C | 2.1°C | 14 mm | 68% | 1 m/s | 6.4 |
| 2022 | 22.7°C | 16.9°C | 11.1°C | 32.0°C | 2.2°C | 152 mm | 79% | 1.2 m/s | 5.3 |
| 2021 | 21.6°C | 15.5°C | 9.4°C | 30.1°C | 2.2°C | 92 mm | 74% | 1.2 m/s | 5.4 |
| 2020 | 19.6°C | 14.1°C | 8.6°C | 27.0°C | -1.8°C | 56 mm | 78% | 1.4 m/s | 5.3 |
| 2019 | 22.6°C | 17.5°C | 12.4°C | 28.2°C | 4.9°C | 162 mm | 82% | 1.3 m/s | 4.9 |
| 2018 🔥 | 24.8°C | 19.2°C | 13.5°C | 29.8°C | 3.8°C | 155 mm | 83% | 1.1 m/s | 4.9 |
| 2017 | 20.8°C | 15.3°C | 9.8°C | 30.6°C | 1.4°C | 133 mm | 78% | 1.4 m/s | 4.6 |
| 2016 | 20.1°C | 15.2°C | 10.2°C | 30.0°C | 1.3°C | 117 mm | 80% | 1.1 m/s | 4.9 |
| 2015 | 24.9°C | 18.9°C | 12.8°C | 30.5°C | 4.1°C | 69 mm | 75% | 1.1 m/s | 6 |
| 2014 | 21.6°C | 15.9°C | 10.3°C | 28.9°C | 3.8°C | 109 mm | 80% | 1.2 m/s | 5.3 |
| 2013 | 21.7°C | 15.9°C | 10.0°C | 31.0°C | 0.0°C | 79 mm | 78% | 1.2 m/s | 5.7 |
| 2012 | 24.2°C | 18.9°C | 13.6°C | 29.9°C | 5.0°C | 130 mm | 80% | 1.1 m/s | 5.2 |
| 2011 | 22.5°C | 17.4°C | 12.4°C | 32.3°C | 4.0°C | 118 mm | 83% | 1.2 m/s | 5 |
| 2010 | 23.0°C | 17.2°C | 11.5°C | 31.3°C | 0.3°C | 94 mm | 78% | 1.2 m/s | 5.3 |
| 2009 | 21.3°C | 16.1°C | 10.8°C | 27.4°C | 5.3°C | 151 mm | 79% | 1.3 m/s | 5.2 |
| 2008 | 19.8°C | 14.0°C | 8.2°C | 26.9°C | 3.5°C | 133 mm | 79% | 1.4 m/s | 5.2 |
| 2007 | 23.4°C | 16.8°C | 10.3°C | 31.0°C | 3.5°C | 40 mm | 74% | 1.1 m/s | 6.7 |
| 2006 | 21.4°C | 15.4°C | 9.5°C | 31.9°C | 3.1°C | 64 mm | 73% | 1.1 m/s | 5.5 |
| 2005 | 19.2°C | 13.2°C | 7.3°C | 27.4°C | 0.7°C | 40 mm | 76% | 1.3 m/s | 5.6 |
| 2004 | 24.3°C | 19.0°C | 13.6°C | 28.4°C | 2.8°C | 118 mm | 81% | 1.2 m/s | 5.4 |
| 2003 | 18.7°C | 14.2°C | 9.7°C | 25.0°C | 4.6°C | 147 mm | 84% | 1.2 m/s | 3.9 |
| 2002 | 21.7°C | 15.2°C | 8.7°C | 30.1°C | 0.9°C | 106 mm | 72% | 1.4 m/s | 5.6 |
| 2001 | 22.5°C | 16.3°C | 10.1°C | 30.5°C | 3.5°C | 77 mm | 70% | 1.2 m/s | 5.6 |
| 2000 | 22.6°C | 16.5°C | 10.5°C | 29.5°C | 2.3°C | 93 mm | 78% | 1.2 m/s | 5.3 |
| 1999 | 23.1°C | 16.4°C | 9.7°C | 31.8°C | 4.2°C | 50 mm | 70% | 1.2 m/s | 6.1 |
| 1998 | 22.3°C | 17.2°C | 12.1°C | 30.4°C | 6.2°C | 138 mm | 82% | 1.1 m/s | 5.5 |
| 1997 ❄️ | 19.4°C | 13.1°C | 6.8°C | 28.5°C | 0.4°C | 74 mm | 72% | 1.6 m/s | 5.8 |
| 1996 | 19.2°C | 13.8°C | 8.3°C | 29.6°C | 0.1°C | 107 mm | 81% | 1.2 m/s | 4.8 |
| 1995 | 20.8°C | 14.9°C | 9.1°C | 28.9°C | 2.1°C | 91 mm | 76% | 1.3 m/s | 5 |
| 1994 | 19.3°C | 13.3°C | 7.2°C | 28.4°C | 2.0°C | 83 mm | 77% | 1.4 m/s | 5.6 |
| 1993 | 21.6°C | 15.8°C | 10.0°C | 27.8°C | 4.9°C | 64 mm | 79% | 1.2 m/s | 5.6 |
| 1992 | 19.7°C | 13.7°C | 7.8°C | 28.5°C | 1.9°C | 102 mm | 77% | 1.2 m/s | 5.3 |
| 1991 | 24.4°C | 18.5°C | 12.6°C | 31.9°C | 4.1°C | 59 mm | 78% | 1.2 m/s | 6 |
| 1990 | 19.8°C | 14.2°C | 8.6°C | 25.3°C | 4.1°C | 169 mm | 78% | 1.4 m/s | 4.5 |
| 1989 🌧️ | 19.5°C | 14.4°C | 9.3°C | 27.8°C | 3.3°C | 228 mm | 82% | 1.4 m/s | 4.1 |
| 1988 | 21.0°C | 15.5°C | 10.1°C | 29.0°C | 3.1°C | 167 mm | 81% | 1.2 m/s | 5.4 |
| 1987 | 21.5°C | 15.5°C | 9.5°C | 30.5°C | 1.3°C | 92 mm | 81% | 1.1 m/s | 5.4 |
| 1986 | 22.2°C | 16.1°C | 10.1°C | 29.1°C | -0.5°C | 50 mm | 76% | 1.2 m/s | 5.9 |
| 1985 | 22.0°C | 15.9°C | 9.9°C | 27.2°C | 0.8°C | 147 mm | 77% | 1.3 m/s | 5.5 |
| 1984 | 19.1°C | 13.7°C | 8.2°C | 26.1°C | 1.5°C | 143 mm | 82% | 1.4 m/s | 4.3 |
| 1983 | 19.5°C | 13.8°C | 8.1°C | 24.6°C | -0.4°C | 132 mm | 80% | 1.4 m/s | — |
| 1982 | 22.6°C | 16.6°C | 10.7°C | 27.5°C | 3.5°C | 86 mm | 78% | 1.1 m/s | — |
| 1981 | 21.4°C | 14.9°C | 8.3°C | 29.3°C | 0.0°C | 86 mm | 74% | 1.2 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 21.6°C with lows near 10.1°C (mean 15.9°C), based on 45 years of NASA POWER data.
May averages 108 mm of rainfall in Mechanicsburg, a relatively wet time of year. The wettest on record was 228 mm in 1989.
The hottest May reached 32.3°C in 2011. The coldest dipped to -1.8°C in 2020.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 1.4°C. Daytime highs moved from 20.9°C to 22.2°C and overnight lows from 9°C to 10.7°C over the same span.
May is one of the warmer months of the year in Mechanicsburg and a relatively wet time of year, so plan for around 21.6°C daytime highs and 10.1°C at night.
Not quite — May is the 8th coolest month in Mechanicsburg, averaging 15.9°C.
For May in Mechanicsburg, pack light layers you can adjust through the day, with typical highs of 21.6°C and lows of 10.1°C. Bring an umbrella or light rain jacket too.
Relative humidity in May averages 78% — quite humid.
Average wind speed in May is 1.2 m/s. The windiest May on record averaged 1.6 m/s (1997).
The wettest May on record was 1989 with 228 mm. On average, May 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 Mechanicsburg 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.
