May is one of the warmer months of the year in Pittsburgh, with average highs near 21.3°C and lows around 9.3°C (mean 15.3°C). It is a relatively wet time of year, averaging 100 mm of rainfall and 78% relative humidity across the period.
May is one of the warmer months of the year in Pittsburgh. Across 45 years of records, the warmest May in Pittsburgh was 2018 — when the month averaged 19.3°C — while the coldest was 1997 at 11.3°C. Typical May days reach 21.3°C with nights near 9.3°C. The long-term trend is warming, about 0.5°C per decade.
May is a relatively wet time of year in Pittsburgh, averaging 100 mm of rainfall. The wettest May on record was 1989 with 162 mm, while the driest was 2007 at 47 mm.
Relative humidity in Pittsburgh during May averages 78%. The most humid May was 2011 at 85%, and the least humid was 2023 at 69%.
May receives about 5.3 kWh/m²/day of solar energy in Pittsburgh. The sunniest May was 2007 at 6.6 kWh/m²/day, and the cloudiest were 1984 and 1989 at 4.2.
Average wind speed in Pittsburgh during May is 0.2 m/s. The windiest Mays were 2023, 2024 and 2025, among others at 0.2 m/s, while the calmest was 2019 at 0.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 14.7°C | 14.6°C | 15.1°C | 16.8°C | 15.5°C | +0.8°C |
| Avg High | 20.8°C | 20.7°C | 21.2°C | 22.6°C | 21.4°C | +0.6°C |
| Avg Low | 8.6°C | 8.5°C | 8.9°C | 11.0°C | 9.5°C | +0.9°C |
| Avg Rain | 114 mm | 96 mm | 97 mm | 96 mm | 99 mm | -14 mm |
May temperatures in Pittsburgh have risen by about 1.5°C between 1981–1985 and 2021–2025.
May has ranged from a record low of -5.1°C (2020) to a record high of 34.3°C (2006).
Rainfall in May is a relatively wet time of year, averaging 100 mm, with a wettest year of 162 mm.
A good time to visit Pittsburgh
May is a good time to visit Pittsburgh, with days averaging 21.3°C and nights around 9.3°C (mean 15.3°C, warmer than Pittsburgh's yearly average) and higher rainfall. August and July 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 | 20.8°C | 15.3°C | 9.8°C | 27.6°C | 0.9°C | 149 mm | 80% | 0.2 m/s | 4.7 |
| 2024 | 23.8°C | 18.1°C | 12.4°C | 30.7°C | 5.5°C | 119 mm | 79% | 0.2 m/s | 5.5 |
| 2023 | 21.3°C | 14.6°C | 7.8°C | 28.8°C | 2.0°C | 48 mm | 69% | 0.2 m/s | 6.1 |
| 2022 | 22.6°C | 16.6°C | 10.6°C | 29.6°C | 2.0°C | 137 mm | 80% | 0.2 m/s | 5.4 |
| 2021 | 21.1°C | 14.7°C | 8.4°C | 29.9°C | -1.7°C | 83 mm | 72% | 0.2 m/s | 5.3 |
| 2020 | 19.0°C | 13.5°C | 7.9°C | 29.2°C | -5.1°C | 58 mm | 78% | 0.2 m/s | 5.3 |
| 2019 | 22.7°C | 17.2°C | 11.6°C | 28.1°C | 4.5°C | 125 mm | 82% | 0.1 m/s | 5 |
| 2018 🔥 | 25.0°C | 19.3°C | 13.7°C | 31.2°C | 2.7°C | 88 mm | 83% | 0.2 m/s | 5.3 |
| 2017 | 20.4°C | 15.0°C | 9.5°C | 27.7°C | -1.1°C | 126 mm | 79% | 0.2 m/s | 5 |
| 2016 | 20.8°C | 15.1°C | 9.5°C | 29.8°C | -0.1°C | 78 mm | 79% | 0.2 m/s | 5.1 |
| 2015 | 24.1°C | 17.9°C | 11.7°C | 29.7°C | 2.2°C | 54 mm | 76% | 0.2 m/s | 5.9 |
| 2014 | 21.6°C | 15.6°C | 9.7°C | 27.3°C | 1.3°C | 99 mm | 79% | 0.2 m/s | 5.2 |
| 2013 | 21.9°C | 15.7°C | 9.5°C | 29.1°C | -0.7°C | 54 mm | 76% | 0.2 m/s | 5.8 |
| 2012 | 24.7°C | 18.6°C | 12.4°C | 31.5°C | 2.6°C | 94 mm | 78% | 0.2 m/s | 5.8 |
| 2011 | 21.7°C | 16.5°C | 11.2°C | 30.6°C | 0.1°C | 115 mm | 85% | 0.2 m/s | 4.8 |
| 2010 | 22.9°C | 16.8°C | 10.7°C | 30.4°C | -0.1°C | 126 mm | 78% | 0.2 m/s | 5.4 |
| 2009 | 21.2°C | 15.4°C | 9.5°C | 29.1°C | 0.0°C | 97 mm | 76% | 0.2 m/s | 5.4 |
| 2008 | 18.9°C | 13.1°C | 7.2°C | 26.5°C | 2.0°C | 107 mm | 78% | 0.2 m/s | 4.9 |
| 2007 | 23.6°C | 16.4°C | 9.2°C | 31.2°C | 2.3°C | 47 mm | 74% | 0.2 m/s | 6.6 |
| 2006 | 20.7°C | 14.4°C | 8.2°C | 34.3°C | -0.5°C | 94 mm | 77% | 0.2 m/s | 5.3 |
| 2005 | 19.1°C | 13.1°C | 7.2°C | 26.7°C | -0.8°C | 73 mm | 76% | 0.2 m/s | 5.5 |
| 2004 | 23.8°C | 17.7°C | 11.7°C | 28.2°C | -1.9°C | 120 mm | 82% | 0.2 m/s | 5.2 |
| 2003 | 19.9°C | 14.8°C | 9.6°C | 24.8°C | 3.9°C | 138 mm | 82% | 0.2 m/s | 4.3 |
| 2002 | 20.2°C | 13.6°C | 7.0°C | 27.8°C | -1.8°C | 114 mm | 76% | 0.2 m/s | 5.2 |
| 2001 | 22.2°C | 15.7°C | 9.2°C | 29.1°C | 2.9°C | 76 mm | 73% | 0.2 m/s | 5.3 |
| 2000 | 22.8°C | 16.5°C | 10.2°C | 28.3°C | 3.3°C | 99 mm | 76% | 0.2 m/s | 5.2 |
| 1999 | 22.9°C | 15.9°C | 8.9°C | 30.4°C | 4.5°C | 83 mm | 72% | 0.2 m/s | 6.3 |
| 1998 | 23.2°C | 17.3°C | 11.4°C | 31.4°C | 5.1°C | 83 mm | 79% | 0.2 m/s | 5.7 |
| 1997 ❄️ | 17.4°C | 11.3°C | 5.3°C | 25.5°C | 0.2°C | 152 mm | 75% | 0.2 m/s | 5.5 |
| 1996 | 19.7°C | 14.1°C | 8.5°C | 28.2°C | -2.0°C | 113 mm | 81% | 0.2 m/s | 4.7 |
| 1995 | 20.0°C | 14.4°C | 8.8°C | 25.8°C | 1.6°C | 142 mm | 79% | 0.2 m/s | 5 |
| 1994 | 18.6°C | 12.3°C | 6.0°C | 26.7°C | 0.5°C | 66 mm | 76% | 0.2 m/s | 5.3 |
| 1993 | 21.4°C | 15.0°C | 8.5°C | 29.1°C | 2.7°C | 58 mm | 75% | 0.2 m/s | 5.4 |
| 1992 | 20.4°C | 13.8°C | 7.3°C | 27.5°C | 1.0°C | 61 mm | 75% | 0.2 m/s | 5.6 |
| 1991 | 24.5°C | 18.7°C | 12.9°C | 29.8°C | 3.2°C | 63 mm | 79% | 0.2 m/s | 5.8 |
| 1990 | 18.6°C | 13.1°C | 7.5°C | 23.7°C | 2.6°C | 144 mm | 79% | 0.2 m/s | 4.6 |
| 1989 🌧️ | 18.0°C | 13.0°C | 8.1°C | 26.7°C | 1.5°C | 162 mm | 83% | 0.2 m/s | 4.2 |
| 1988 | 21.8°C | 15.4°C | 8.9°C | 29.5°C | 1.1°C | 91 mm | 75% | 0.2 m/s | 5.6 |
| 1987 | 22.8°C | 16.4°C | 10.0°C | 29.4°C | -0.2°C | 99 mm | 78% | 0.2 m/s | 5.8 |
| 1986 | 21.5°C | 15.4°C | 9.3°C | 27.3°C | -2.9°C | 69 mm | 78% | 0.2 m/s | 5.4 |
| 1985 | 21.5°C | 15.3°C | 9.0°C | 27.5°C | 0.9°C | 159 mm | 79% | 0.2 m/s | 5.7 |
| 1984 | 18.4°C | 12.8°C | 7.3°C | 26.4°C | 0.1°C | 135 mm | 80% | 0.2 m/s | 4.2 |
| 1983 | 18.8°C | 12.6°C | 6.5°C | 24.6°C | -4.3°C | 143 mm | 79% | 0.2 m/s | — |
| 1982 | 23.9°C | 17.6°C | 11.4°C | 29.4°C | 3.6°C | 92 mm | 78% | 0.2 m/s | — |
| 1981 | 20.2°C | 13.7°C | 7.3°C | 26.0°C | -1.9°C | 74 mm | 74% | 0.2 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 21.3°C with lows near 9.3°C (mean 15.3°C), based on 45 years of NASA POWER data.
May averages 100 mm of rainfall in Pittsburgh, a relatively wet time of year. The wettest on record was 162 mm in 1989.
The hottest May reached 34.3°C in 2006. The coldest dipped to -5.1°C in 2020.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 1.5°C. Daytime highs moved from 20.6°C to 21.9°C and overnight lows from 8.3°C to 9.8°C over the same span.
May is one of the warmer months of the year in Pittsburgh and a relatively wet time of year, so plan for around 21.3°C daytime highs and 9.3°C at night.
Not quite — May is the 8th coolest month in Pittsburgh, averaging 15.3°C.
For May in Pittsburgh, pack light layers you can adjust through the day, with typical highs of 21.3°C and lows of 9.3°C. Bring an umbrella or light rain jacket too.
Relative humidity in May averages 78% — quite humid.
Average wind speed in May is 0.2 m/s. The windiest May on record averaged 0.2 m/s (1981).
The wettest May on record was 1989 with 162 mm. On average, May sees 100 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 Pittsburgh 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.
