May is one of the warmer months of the year in Knoxville, with average highs near 24.1°C and lows around 12.8°C (mean 18.5°C). It is about average for rainfall, averaging 114 mm of rainfall and 77% relative humidity across the period.
May is one of the warmer months of the year in Knoxville. Across 45 years of records, the warmest May in Knoxville was 2018 — when the month averaged 21.3°C — while the coldest was 1989 at 15.4°C. Typical May days reach 24.1°C with nights near 12.8°C. The long-term trend is warming, about 0.3°C per decade.
May is about average for rainfall in Knoxville, averaging 114 mm of rainfall. The wettest May on record was 1984 with 244 mm, while the driest was 2007 at 36 mm.
Relative humidity in Knoxville during May averages 77%. The most humid May was 2003 at 83%, and the least humid was 2007 at 61%.
May receives about 5.7 kWh/m²/day of solar energy in Knoxville. The sunniest May was 2007 at 6.6 kWh/m²/day, and the cloudiest was 2025 at 4.8.
Average wind speed in Knoxville during May is 0.8 m/s. The windiest Mays were 1989, 1997 and 2008, among others at 1 m/s, while the calmest were 1987 and 1991 at 0.6 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 17.8°C | 18.0°C | 18.6°C | 19.4°C | 18.4°C | +0.6°C |
| Avg High | 23.8°C | 23.5°C | 24.3°C | 24.7°C | 23.8°C | 0°C |
| Avg Low | 11.9°C | 12.5°C | 12.8°C | 14.0°C | 13.1°C | +1.2°C |
| Avg Rain | 128 mm | 113 mm | 108 mm | 99 mm | 134 mm | +6 mm |
May temperatures in Knoxville have risen by about 1.1°C between 1981–1985 and 2021–2025.
May has ranged from a record low of 1.1°C (1989) to a record high of 33.5°C (2007).
Rainfall in May is about average for rainfall, averaging 114 mm, with a wettest year of 244 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.2°C per decade while lows rose 0.5°C per decade, narrowing the gap between day and night.
A good time to visit Knoxville
May is a good time to visit Knoxville, with days averaging 24.1°C and nights around 12.8°C (mean 18.5°C, warmer than Knoxville's yearly average) and higher rainfall. September 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 | 23.3°C | 18.4°C | 13.6°C | 26.6°C | 8.6°C | 185 mm | 81% | 0.9 m/s | 4.8 |
| 2024 | 25.0°C | 19.9°C | 14.8°C | 28.6°C | 8.7°C | 199 mm | 81% | 0.8 m/s | 5.4 |
| 2023 | 23.6°C | 18.0°C | 12.4°C | 27.7°C | 4.6°C | 64 mm | 77% | 0.8 m/s | 5.6 |
| 2022 | 25.6°C | 19.9°C | 14.1°C | 31.2°C | 8.9°C | 134 mm | 77% | 0.8 m/s | 5.9 |
| 2021 | 23.0°C | 17.5°C | 12.1°C | 29.6°C | 4.3°C | 99 mm | 77% | 0.8 m/s | 5.7 |
| 2020 | 22.3°C | 16.8°C | 11.3°C | 28.5°C | 1.5°C | 121 mm | 81% | 0.9 m/s | 5.7 |
| 2019 | 25.9°C | 20.7°C | 15.6°C | 30.1°C | 7.4°C | 112 mm | 80% | 0.8 m/s | 6.4 |
| 2018 🔥 | 26.3°C | 21.3°C | 16.4°C | 29.7°C | 7.0°C | 120 mm | 82% | 0.7 m/s | 5.6 |
| 2017 | 23.9°C | 18.5°C | 13.2°C | 29.1°C | 4.8°C | 140 mm | 79% | 0.9 m/s | 5.7 |
| 2016 | 23.2°C | 17.8°C | 12.4°C | 29.0°C | 3.4°C | 88 mm | 79% | 0.8 m/s | 5.9 |
| 2015 | 25.7°C | 19.8°C | 14.0°C | 28.5°C | 6.5°C | 51 mm | 76% | 0.7 m/s | 6.3 |
| 2014 | 24.8°C | 19.1°C | 13.4°C | 29.7°C | 5.9°C | 69 mm | 76% | 0.8 m/s | 6.1 |
| 2013 | 22.8°C | 17.5°C | 12.1°C | 28.2°C | 3.6°C | 104 mm | 80% | 0.8 m/s | 5.8 |
| 2012 | 25.5°C | 20.4°C | 15.3°C | 30.3°C | 6.4°C | 103 mm | 79% | 0.7 m/s | 5.9 |
| 2011 | 23.6°C | 18.3°C | 13.0°C | 32.0°C | 1.7°C | 69 mm | 78% | 0.8 m/s | 5.8 |
| 2010 | 25.6°C | 20.1°C | 14.6°C | 29.4°C | 4.8°C | 130 mm | 79% | 0.8 m/s | 5.7 |
| 2009 | 23.4°C | 18.4°C | 13.3°C | 26.9°C | 3.5°C | 181 mm | 82% | 0.9 m/s | 5.2 |
| 2008 | 23.5°C | 17.6°C | 11.7°C | 29.2°C | 6.2°C | 77 mm | 73% | 1 m/s | 5.9 |
| 2007 | 27.4°C | 20.3°C | 13.1°C | 33.5°C | 5.3°C | 36 mm | 61% | 0.7 m/s | 6.6 |
| 2006 | 23.3°C | 17.7°C | 12.0°C | 32.6°C | 7.0°C | 88 mm | 77% | 0.8 m/s | 5.6 |
| 2005 | 22.5°C | 16.7°C | 11.0°C | 28.2°C | 2.6°C | 71 mm | 77% | 0.8 m/s | 6 |
| 2004 | 26.0°C | 20.6°C | 15.2°C | 30.3°C | 3.3°C | 118 mm | 77% | 0.9 m/s | 5.5 |
| 2003 | 23.3°C | 18.5°C | 13.7°C | 27.4°C | 8.6°C | 197 mm | 83% | 0.9 m/s | 5 |
| 2002 | 23.4°C | 17.3°C | 11.2°C | 28.5°C | 2.7°C | 111 mm | 76% | 0.9 m/s | 5.8 |
| 2001 | 25.1°C | 19.0°C | 12.9°C | 30.5°C | 7.4°C | 92 mm | 72% | 0.9 m/s | 5.6 |
| 2000 | 25.3°C | 19.5°C | 13.7°C | 28.5°C | 7.5°C | 113 mm | 75% | 0.9 m/s | 5.7 |
| 1999 | 24.1°C | 18.0°C | 12.0°C | 27.6°C | 4.2°C | 106 mm | 74% | 0.8 m/s | 6.5 |
| 1998 | 25.0°C | 20.1°C | 15.1°C | 30.2°C | 7.4°C | 113 mm | 82% | 0.8 m/s | 5.8 |
| 1997 | 21.5°C | 15.5°C | 9.6°C | 26.7°C | 3.8°C | 129 mm | 77% | 1 m/s | 6.1 |
| 1996 | 24.5°C | 19.2°C | 13.9°C | 30.0°C | 3.3°C | 147 mm | 81% | 0.9 m/s | 6 |
| 1995 | 24.5°C | 18.7°C | 13.0°C | 29.0°C | 5.8°C | 124 mm | 76% | 0.9 m/s | 5.4 |
| 1994 | 22.0°C | 15.9°C | 9.8°C | 27.5°C | 4.2°C | 69 mm | 78% | 0.9 m/s | 6.3 |
| 1993 | 23.5°C | 18.1°C | 12.6°C | 27.6°C | 6.5°C | 86 mm | 78% | 0.8 m/s | 5.3 |
| 1992 | 21.8°C | 16.5°C | 11.2°C | 26.9°C | 4.4°C | 81 mm | 79% | 0.7 m/s | 5.3 |
| 1991 | 25.9°C | 20.7°C | 15.6°C | 30.5°C | 6.5°C | 118 mm | 82% | 0.6 m/s | 5.1 |
| 1990 | 22.5°C | 17.1°C | 11.8°C | 26.5°C | 4.5°C | 158 mm | 80% | 0.9 m/s | 5.4 |
| 1989 ❄️ | 21.1°C | 15.4°C | 9.6°C | 28.3°C | 1.1°C | 144 mm | 80% | 1 m/s | 5 |
| 1988 | 24.3°C | 17.8°C | 11.3°C | 32.2°C | 4.3°C | 76 mm | 67% | 0.9 m/s | 6 |
| 1987 | 25.5°C | 20.2°C | 14.9°C | 29.3°C | 7.8°C | 109 mm | 79% | 0.6 m/s | 5.8 |
| 1986 | 25.6°C | 19.2°C | 12.7°C | 28.9°C | 1.6°C | 100 mm | 69% | 0.8 m/s | 5.3 |
| 1985 | 24.9°C | 18.6°C | 12.2°C | 31.0°C | 5.6°C | 66 mm | 72% | 0.9 m/s | 5.3 |
| 1984 🌧️ | 22.0°C | 16.2°C | 10.4°C | 27.4°C | 3.8°C | 244 mm | 80% | 1 m/s | 5.4 |
| 1983 | 22.4°C | 16.6°C | 10.8°C | 27.8°C | 3.4°C | 176 mm | 78% | 1 m/s | — |
| 1982 | 25.2°C | 19.8°C | 14.5°C | 29.0°C | 6.6°C | 115 mm | 78% | 0.7 m/s | — |
| 1981 | 23.0°C | 16.7°C | 10.3°C | 28.0°C | 5.4°C | 118 mm | 72% | 0.9 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 24.1°C with lows near 12.8°C (mean 18.5°C), based on 45 years of NASA POWER data.
May averages 114 mm of rainfall in Knoxville, about average for rainfall. The wettest on record was 244 mm in 1984.
The hottest May reached 33.5°C in 2007. The coldest dipped to 1.1°C in 1989.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 1.1°C. Daytime highs moved from 23.5°C to 24.1°C and overnight lows from 11.6°C to 13.4°C over the same span.
May is one of the warmer months of the year in Knoxville and about average for rainfall, so plan for around 24.1°C daytime highs and 12.8°C at night.
Not quite — May is the 8th coolest month in Knoxville, averaging 18.5°C.
For May in Knoxville, pack light layers you can adjust through the day, with typical highs of 24.1°C and lows of 12.8°C. Bring an umbrella or light rain jacket too.
Relative humidity in May averages 77% — quite humid.
Average wind speed in May is 0.8 m/s. The windiest May on record averaged 1 m/s (1983).
The wettest May on record was 1984 with 244 mm. On average, May sees 114 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 Knoxville 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.
