May is one of the warmer months of the year in Altoona, with average highs near 20.8°C and lows around 8.7°C (mean 14.8°C). It is a relatively wet time of year, averaging 105 mm of rainfall and 78% relative humidity across the period.
May is one of the warmer months of the year in Altoona. Across 45 years of records, the warmest May in Altoona was 2018 — when the month averaged 18.3°C — while the coldest was 1997 at 11.4°C. Typical May days reach 20.8°C with nights near 8.7°C. The long-term trend is warming, about 0.4°C per decade.
May is a relatively wet time of year in Altoona, averaging 105 mm of rainfall. The wettest May on record was 2025 with 213 mm, while the driest was 2023 at 26 mm.
Relative humidity in Altoona during May averages 78%. The most humid May was 2003 at 84%, and the least humid was 2001 at 68%.
May receives about 5.2 kWh/m²/day of solar energy in Altoona. The sunniest May was 2007 at 6.5 kWh/m²/day, and the cloudiest was 2003 at 3.9.
Average wind speed in Altoona during May is 0.1 m/s. The windiest Mays were 2022, 2023 and 2024, among others at 0.1 m/s, while the calmest were 2019, 2020 and 2025, among others at 0 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 14.1°C | 14.0°C | 14.5°C | 16.2°C | 14.8°C | +0.7°C |
| Avg High | 20.2°C | 20.2°C | 20.7°C | 22.0°C | 20.7°C | +0.5°C |
| Avg Low | 8.0°C | 7.9°C | 8.3°C | 10.4°C | 8.9°C | +0.9°C |
| Avg Rain | 114 mm | 85 mm | 99 mm | 119 mm | 111 mm | -4 mm |
May temperatures in Altoona have risen by about 1.3°C between 1981–1985 and 2021–2025.
May has ranged from a record low of -3.7°C (2020) to a record high of 35.6°C (2006).
Rainfall in May is a relatively wet time of year, averaging 105 mm, with a wettest year of 213 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 Altoona
May is a good time to visit Altoona, with days averaging 20.8°C and nights around 8.7°C (mean 14.8°C, warmer than Altoona'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 🌧️ | 20.4°C | 15.0°C | 9.7°C | 27.6°C | 3.2°C | 213 mm | 80% | 0 m/s | 4.5 |
| 2024 | 22.2°C | 17.0°C | 11.8°C | 27.8°C | 4.6°C | 123 mm | 81% | 0.1 m/s | 5.2 |
| 2023 | 21.1°C | 14.1°C | 7.0°C | 29.4°C | 0.3°C | 26 mm | 69% | 0.1 m/s | 6.2 |
| 2022 | 21.7°C | 15.7°C | 9.7°C | 29.6°C | 0.4°C | 142 mm | 79% | 0.1 m/s | 5.3 |
| 2021 | 20.2°C | 14.0°C | 7.9°C | 28.6°C | 0.2°C | 109 mm | 75% | 0.1 m/s | 5.3 |
| 2020 | 18.3°C | 12.7°C | 7.2°C | 26.3°C | -3.7°C | 49 mm | 78% | 0 m/s | 5.2 |
| 2019 | 22.0°C | 16.6°C | 11.2°C | 26.4°C | 3.5°C | 168 mm | 83% | 0 m/s | 4.9 |
| 2018 🔥 | 24.0°C | 18.3°C | 12.7°C | 30.3°C | 3.4°C | 132 mm | 84% | 0 m/s | 5.1 |
| 2017 | 19.6°C | 14.1°C | 8.6°C | 28.2°C | -1.9°C | 155 mm | 79% | 0 m/s | 4.7 |
| 2016 | 19.9°C | 14.5°C | 9.1°C | 30.0°C | 1.7°C | 95 mm | 79% | 0.1 m/s | 4.9 |
| 2015 | 24.7°C | 18.0°C | 11.2°C | 29.8°C | 0.9°C | 49 mm | 74% | 0.1 m/s | 5.9 |
| 2014 | 21.0°C | 15.0°C | 9.1°C | 27.5°C | 1.4°C | 113 mm | 78% | 0.1 m/s | 5.2 |
| 2013 | 21.0°C | 14.9°C | 8.7°C | 29.0°C | -0.8°C | 68 mm | 78% | 0 m/s | 5.6 |
| 2012 | 23.8°C | 18.2°C | 12.6°C | 31.2°C | 4.1°C | 158 mm | 79% | 0.1 m/s | 5.4 |
| 2011 | 21.7°C | 16.4°C | 11.1°C | 30.3°C | 1.2°C | 137 mm | 84% | 0 m/s | 4.8 |
| 2010 | 21.8°C | 16.0°C | 10.1°C | 29.3°C | -1.4°C | 119 mm | 79% | 0.1 m/s | 5.2 |
| 2009 | 20.5°C | 14.7°C | 9.0°C | 27.2°C | 0.8°C | 120 mm | 77% | 0.1 m/s | 5.1 |
| 2008 | 18.7°C | 12.6°C | 6.6°C | 26.4°C | 0.8°C | 132 mm | 79% | 0.1 m/s | 5.1 |
| 2007 | 23.1°C | 15.9°C | 8.8°C | 32.8°C | 1.8°C | 53 mm | 72% | 0.1 m/s | 6.5 |
| 2006 | 20.5°C | 14.2°C | 8.0°C | 35.6°C | 0.5°C | 63 mm | 74% | 0.1 m/s | 5.4 |
| 2005 | 18.4°C | 12.2°C | 5.9°C | 26.3°C | -0.4°C | 46 mm | 76% | 0.1 m/s | 5.4 |
| 2004 | 23.7°C | 17.7°C | 11.7°C | 28.2°C | 0.6°C | 127 mm | 81% | 0.1 m/s | 5.3 |
| 2003 | 18.1°C | 13.1°C | 8.2°C | 24.2°C | 3.2°C | 147 mm | 84% | 0.1 m/s | 3.9 |
| 2002 | 20.2°C | 13.5°C | 6.9°C | 27.9°C | -2.4°C | 133 mm | 75% | 0 m/s | 5.3 |
| 2001 | 22.0°C | 15.3°C | 8.5°C | 30.3°C | 2.8°C | 63 mm | 68% | 0.1 m/s | 5.4 |
| 2000 | 22.2°C | 16.0°C | 9.8°C | 29.1°C | 2.1°C | 103 mm | 77% | 0.1 m/s | 5.2 |
| 1999 | 22.2°C | 15.4°C | 8.6°C | 30.9°C | 3.3°C | 46 mm | 70% | 0.1 m/s | 6.2 |
| 1998 | 22.0°C | 16.5°C | 11.0°C | 29.6°C | 5.5°C | 110 mm | 81% | 0.1 m/s | 5.6 |
| 1997 ❄️ | 17.7°C | 11.4°C | 5.1°C | 26.3°C | -0.8°C | 114 mm | 73% | 0 m/s | 5.6 |
| 1996 | 18.8°C | 13.0°C | 7.2°C | 28.3°C | -1.9°C | 99 mm | 81% | 0.1 m/s | 4.6 |
| 1995 | 19.8°C | 13.8°C | 7.7°C | 26.3°C | -0.1°C | 99 mm | 77% | 0 m/s | 5.1 |
| 1994 | 18.4°C | 11.9°C | 5.5°C | 26.7°C | -0.4°C | 75 mm | 76% | 0 m/s | 5.2 |
| 1993 | 20.9°C | 14.6°C | 8.4°C | 27.2°C | 2.3°C | 51 mm | 78% | 0 m/s | 5.6 |
| 1992 | 19.6°C | 13.3°C | 7.0°C | 27.6°C | 0.9°C | 67 mm | 75% | 0.1 m/s | 5.2 |
| 1991 | 23.6°C | 17.6°C | 11.7°C | 29.0°C | 3.1°C | 50 mm | 79% | 0.1 m/s | 5.8 |
| 1990 | 18.5°C | 12.8°C | 7.2°C | 24.7°C | 2.3°C | 142 mm | 77% | 0.1 m/s | 4.6 |
| 1989 | 18.2°C | 13.1°C | 8.0°C | 26.9°C | 1.6°C | 167 mm | 83% | 0.1 m/s | 4 |
| 1988 | 20.7°C | 14.7°C | 8.7°C | 28.0°C | 0.4°C | 135 mm | 79% | 0.1 m/s | 5.4 |
| 1987 | 21.5°C | 15.0°C | 8.5°C | 29.1°C | -1.1°C | 94 mm | 80% | 0.1 m/s | 5.6 |
| 1986 | 21.1°C | 15.0°C | 8.9°C | 27.8°C | -1.5°C | 67 mm | 78% | 0 m/s | 5.5 |
| 1985 | 21.0°C | 14.8°C | 8.6°C | 26.1°C | -1.6°C | 134 mm | 79% | 0.1 m/s | 5.6 |
| 1984 | 18.0°C | 12.4°C | 6.9°C | 25.7°C | -0.5°C | 118 mm | 80% | 0 m/s | 4.1 |
| 1983 | 18.6°C | 12.4°C | 6.2°C | 24.3°C | -2.6°C | 127 mm | 79% | 0.1 m/s | — |
| 1982 | 22.4°C | 16.1°C | 9.7°C | 27.0°C | 2.4°C | 100 mm | 79% | 0.1 m/s | — |
| 1981 | 20.2°C | 13.6°C | 6.9°C | 27.0°C | -1.7°C | 87 mm | 74% | 0.1 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 20.8°C with lows near 8.7°C (mean 14.8°C), based on 45 years of NASA POWER data.
May averages 105 mm of rainfall in Altoona, a relatively wet time of year. The wettest on record was 213 mm in 2025.
The hottest May reached 35.6°C in 2006. The coldest dipped to -3.7°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 20°C to 21.1°C and overnight lows from 7.7°C to 9.2°C over the same span.
May is one of the warmer months of the year in Altoona and a relatively wet time of year, so plan for around 20.8°C daytime highs and 8.7°C at night.
Not quite — May is the 8th coolest month in Altoona, averaging 14.8°C.
For May in Altoona, pack light layers you can adjust through the day, with typical highs of 20.8°C and lows of 8.7°C. Bring an umbrella or light rain jacket too.
Relative humidity in May averages 78% — quite humid.
Average wind speed in May is 0.1 m/s. The windiest May on record averaged 0.1 m/s (1981).
The wettest May on record was 2025 with 213 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 Altoona 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.
