May is one of the warmer months of the year in Normal, with average highs near 22.2°C and lows around 10.4°C (mean 16.3°C). It is a relatively wet time of year, averaging 110 mm of rainfall and 76% relative humidity across the period.
May is one of the warmer months of the year in Normal. Across 45 years of records, the warmest May in Normal was 2018 — when the month averaged 20.8°C — while the coldest was 1983 at 13.2°C. Typical May days reach 22.2°C with nights near 10.4°C. The long-term trend is warming, about 0.4°C per decade.
May is a relatively wet time of year in Normal, averaging 110 mm of rainfall. The wettest May on record was 1995 with 255 mm, while the driest was 1992 at 21 mm.
Relative humidity in Normal during May averages 76%. The most humid May was 1991 at 84%, and the least humid was 1988 at 66%.
May receives about 5.5 kWh/m²/day of solar energy in Normal. The sunniest Mays were 1988 and 1994 at 6.7 kWh/m²/day, and the cloudiest were 1995 and 1996 at 4.5.
Average wind speed in Normal during May is 3.3 m/s. The windiest Mays were 1985, 1997 and 2008 at 3.8 m/s, while the calmest were 1991, 1994 and 2023 at 2.8 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 15.7°C | 15.8°C | 16.2°C | 17.3°C | 16.7°C | +1°C |
| Avg High | 21.8°C | 21.6°C | 22.2°C | 23.0°C | 22.6°C | +0.8°C |
| Avg Low | 9.5°C | 10.0°C | 10.3°C | 11.6°C | 10.8°C | +1.3°C |
| Avg Rain | 96 mm | 124 mm | 106 mm | 121 mm | 99 mm | +4 mm |
May temperatures in Normal have risen by about 1.9°C between 1981–1985 and 2021–2025.
May has ranged from a record low of -2.8°C (1989) to a record high of 33.5°C (2012).
Rainfall in May is a relatively wet time of year, averaging 110 mm, with a wettest year of 255 mm.
A good time to visit Normal
May is a good time to visit Normal, with days averaging 22.2°C and nights around 10.4°C (mean 16.3°C, warmer than Normal's yearly average) and higher rainfall. August and June 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 | 22.1°C | 16.0°C | 9.8°C | 30.8°C | 4.1°C | 79 mm | 73% | 3.2 m/s | 5.5 |
| 2024 | 24.5°C | 18.6°C | 12.6°C | 29.7°C | 7.9°C | 117 mm | 75% | 3 m/s | 6 |
| 2023 | 24.1°C | 17.5°C | 11.0°C | 31.1°C | 1.5°C | 56 mm | 68% | 2.8 m/s | 6.4 |
| 2022 | 23.0°C | 17.5°C | 12.0°C | 31.0°C | 3.8°C | 93 mm | 79% | 3.7 m/s | 5.2 |
| 2021 | 21.3°C | 15.6°C | 9.8°C | 29.5°C | 0.9°C | 117 mm | 72% | 3.2 m/s | 5.4 |
| 2020 | 20.4°C | 15.0°C | 9.6°C | 29.0°C | 0.4°C | 134 mm | 79% | 3.2 m/s | 5.3 |
| 2019 | 21.9°C | 16.8°C | 11.6°C | 27.9°C | 4.7°C | 167 mm | 81% | 3.4 m/s | 5.1 |
| 2018 🔥 | 26.7°C | 20.8°C | 14.9°C | 33.2°C | 8.0°C | 68 mm | 77% | 2.9 m/s | 6 |
| 2017 | 21.4°C | 15.6°C | 9.8°C | 28.6°C | 3.1°C | 121 mm | 77% | 3.6 m/s | 5.7 |
| 2016 | 21.7°C | 16.1°C | 10.4°C | 28.5°C | 1.6°C | 91 mm | 76% | 3 m/s | 5.6 |
| 2015 | 23.5°C | 17.8°C | 12.1°C | 28.1°C | 2.5°C | 140 mm | 76% | 3.5 m/s | 5.5 |
| 2014 | 22.7°C | 16.9°C | 11.1°C | 29.5°C | 2.3°C | 64 mm | 74% | 3.4 m/s | 5.8 |
| 2013 | 22.5°C | 17.1°C | 11.8°C | 29.0°C | 1.1°C | 205 mm | 81% | 3.5 m/s | 5.1 |
| 2012 | 25.6°C | 19.1°C | 12.6°C | 33.5°C | 6.4°C | 70 mm | 69% | 3.2 m/s | 6.6 |
| 2011 | 21.4°C | 16.0°C | 10.5°C | 30.1°C | 0.2°C | 136 mm | 82% | 3.4 m/s | 4.8 |
| 2010 | 22.4°C | 16.8°C | 11.2°C | 30.2°C | 0.9°C | 149 mm | 80% | 3.3 m/s | 5.5 |
| 2009 | 21.4°C | 15.6°C | 9.7°C | 27.8°C | 1.2°C | 132 mm | 78% | 2.9 m/s | 5.7 |
| 2008 | 19.8°C | 14.0°C | 8.2°C | 27.6°C | 2.2°C | 123 mm | 77% | 3.8 m/s | 5.1 |
| 2007 | 24.1°C | 18.5°C | 12.9°C | 29.3°C | 4.8°C | 58 mm | 76% | 3.3 m/s | 5.6 |
| 2006 | 21.3°C | 15.9°C | 10.5°C | 31.1°C | 3.6°C | 65 mm | 76% | 3.2 m/s | 5.6 |
| 2005 | 21.8°C | 15.4°C | 8.9°C | 28.1°C | -2.2°C | 33 mm | 71% | 3.3 m/s | 6.2 |
| 2004 | 24.0°C | 18.3°C | 12.6°C | 30.1°C | -0.5°C | 162 mm | 78% | 3.7 m/s | 5.4 |
| 2003 | 22.2°C | 15.8°C | 9.4°C | 29.5°C | 1.7°C | 107 mm | 72% | 3.7 m/s | 5.4 |
| 2002 | 20.2°C | 13.8°C | 7.4°C | 30.3°C | -1.1°C | 160 mm | 78% | 3.6 m/s | 5.4 |
| 2001 | 22.9°C | 17.2°C | 11.4°C | 30.3°C | 4.8°C | 110 mm | 73% | 3.5 m/s | 5.2 |
| 2000 | 24.2°C | 17.9°C | 11.7°C | 30.1°C | 3.7°C | 105 mm | 72% | 3.7 m/s | 4.8 |
| 1999 | 23.0°C | 16.9°C | 10.9°C | 27.2°C | 4.8°C | 118 mm | 75% | 3.6 m/s | 5.8 |
| 1998 | 24.2°C | 18.6°C | 13.0°C | 29.7°C | 6.4°C | 137 mm | 80% | 3 m/s | 5.7 |
| 1997 | 19.5°C | 13.4°C | 7.2°C | 28.5°C | 2.4°C | 76 mm | 70% | 3.8 m/s | 5.5 |
| 1996 | 21.6°C | 15.8°C | 9.9°C | 30.3°C | 2.5°C | 192 mm | 77% | 3.5 m/s | 4.5 |
| 1995 🌧️ | 20.1°C | 14.7°C | 9.3°C | 24.6°C | 4.1°C | 255 mm | 78% | 3.3 m/s | 4.5 |
| 1994 | 20.8°C | 14.3°C | 7.9°C | 28.1°C | 0.6°C | 51 mm | 76% | 2.8 m/s | 6.7 |
| 1993 | 21.5°C | 15.9°C | 10.4°C | 27.1°C | 2.5°C | 61 mm | 79% | 3.4 m/s | 5.2 |
| 1992 | 21.1°C | 14.6°C | 8.2°C | 27.9°C | -0.4°C | 21 mm | 72% | 3 m/s | 5.8 |
| 1991 | 24.1°C | 19.2°C | 14.3°C | 30.8°C | 3.3°C | 152 mm | 84% | 2.8 m/s | 5.4 |
| 1990 | 20.1°C | 14.3°C | 8.4°C | 25.0°C | 1.7°C | 177 mm | 77% | 3.7 m/s | 5 |
| 1989 | 20.5°C | 14.3°C | 8.0°C | 29.3°C | -2.8°C | 91 mm | 72% | 3.3 m/s | 5.4 |
| 1988 | 24.1°C | 16.6°C | 9.1°C | 30.5°C | 1.9°C | 39 mm | 66% | 3.2 m/s | 6.7 |
| 1987 | 24.7°C | 18.6°C | 12.6°C | 28.8°C | 2.8°C | 60 mm | 74% | 3 m/s | 6.3 |
| 1986 | 22.1°C | 16.4°C | 10.7°C | 27.5°C | 2.4°C | 88 mm | 76% | 3.1 m/s | 5.3 |
| 1985 | 22.6°C | 16.6°C | 10.5°C | 28.9°C | 3.3°C | 69 mm | 74% | 3.8 m/s | 6 |
| 1984 | 19.3°C | 13.4°C | 7.5°C | 26.8°C | 1.2°C | 140 mm | 78% | 3.4 m/s | 5.1 |
| 1983 ❄️ | 19.0°C | 13.2°C | 7.4°C | 23.7°C | -2.0°C | 102 mm | 79% | 3.6 m/s | — |
| 1982 | 24.4°C | 18.7°C | 12.9°C | 27.1°C | 7.6°C | 119 mm | 78% | 3 m/s | — |
| 1981 | 19.8°C | 13.5°C | 7.2°C | 26.9°C | 0.4°C | 152 mm | 74% | 3.7 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 22.2°C with lows near 10.4°C (mean 16.3°C), based on 45 years of NASA POWER data.
May averages 110 mm of rainfall in Normal, a relatively wet time of year. The wettest on record was 255 mm in 1995.
The hottest May reached 33.5°C in 2012. The coldest dipped to -2.8°C in 1989.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 1.9°C. Daytime highs moved from 21°C to 23°C and overnight lows from 9.1°C to 11°C over the same span.
May is one of the warmer months of the year in Normal and a relatively wet time of year, so plan for around 22.2°C daytime highs and 10.4°C at night.
Not quite — May is the 8th coolest month in Normal, averaging 16.3°C.
For May in Normal, pack light layers you can adjust through the day, with typical highs of 22.2°C and lows of 10.4°C. Bring an umbrella or light rain jacket too.
Relative humidity in May averages 76% — quite humid.
Average wind speed in May is 3.3 m/s. The windiest May on record averaged 3.8 m/s (1985).
The wettest May on record was 1995 with 255 mm. On average, May sees 110 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 Normal 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.
