May is one of the warmer months of the year in Morristown, with average highs near 23.1°C and lows around 11.9°C (mean 17.5°C). It is a relatively wet time of year, averaging 115 mm of rainfall and 78% relative humidity across the period.
May is one of the warmer months of the year in Morristown. Across 45 years of records, the warmest May in Morristown was 2018 — when the month averaged 20.3°C — while the coldest were 1989 and 1997 at 14.4°C. Typical May days reach 23.1°C with nights near 11.9°C. The long-term trend is warming, about 0.4°C per decade.
May is a relatively wet time of year in Morristown, averaging 115 mm of rainfall. The wettest May on record was 1984 with 230 mm, while the driest was 2007 at 38 mm.
Relative humidity in Morristown during May averages 78%. The most humid May was 2003 at 84%, and the least humid was 2007 at 63%.
May receives about 5.7 kWh/m²/day of solar energy in Morristown. The sunniest May was 1999 at 6.7 kWh/m²/day, and the cloudiest was 2003 at 4.9.
Average wind speed in Morristown during May is 0.6 m/s. The windiest Mays were 2003, 2008 and 2017, among others at 0.7 m/s, while the calmest were 2012, 2015 and 2018, among others at 0.5 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 16.9°C | 17.0°C | 17.6°C | 18.5°C | 17.5°C | +0.6°C |
| Avg High | 22.8°C | 22.5°C | 23.4°C | 23.8°C | 22.9°C | +0.1°C |
| Avg Low | 10.9°C | 11.5°C | 11.9°C | 13.2°C | 12.1°C | +1.2°C |
| Avg Rain | 125 mm | 113 mm | 106 mm | 105 mm | 135 mm | +10 mm |
May temperatures in Morristown have risen by about 1.2°C between 1981–1985 and 2021–2025.
May has ranged from a record low of -0.5°C (1989) to a record high of 32.4°C (2007).
Rainfall in May is a relatively wet time of year, averaging 115 mm, with a wettest year of 230 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 Morristown
May is a good time to visit Morristown, with days averaging 23.1°C and nights around 11.9°C (mean 17.5°C, warmer than Morristown's yearly average) and higher rainfall. June and September 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 | 22.6°C | 17.6°C | 12.7°C | 26.1°C | 7.1°C | 159 mm | 80% | 0.6 m/s | 5.2 |
| 2024 | 24.2°C | 19.1°C | 14.0°C | 28.4°C | 7.8°C | 183 mm | 81% | 0.6 m/s | 5.3 |
| 2023 | 22.7°C | 17.1°C | 11.5°C | 26.7°C | 3.8°C | 80 mm | 77% | 0.6 m/s | 5.8 |
| 2022 | 24.8°C | 18.9°C | 13.0°C | 29.8°C | 6.9°C | 162 mm | 77% | 0.6 m/s | 6 |
| 2021 | 22.0°C | 16.6°C | 11.2°C | 28.5°C | 2.8°C | 90 mm | 78% | 0.6 m/s | 5.8 |
| 2020 | 21.1°C | 15.7°C | 10.4°C | 26.8°C | 0.7°C | 137 mm | 82% | 0.6 m/s | 5.7 |
| 2019 | 25.1°C | 19.9°C | 14.8°C | 29.8°C | 6.6°C | 105 mm | 80% | 0.6 m/s | 6.2 |
| 2018 🔥 | 25.3°C | 20.3°C | 15.4°C | 28.9°C | 6.5°C | 166 mm | 82% | 0.5 m/s | 5.8 |
| 2017 | 23.0°C | 17.8°C | 12.7°C | 29.5°C | 5.0°C | 140 mm | 79% | 0.7 m/s | 5.6 |
| 2016 | 22.1°C | 16.9°C | 11.6°C | 28.1°C | 2.3°C | 98 mm | 80% | 0.6 m/s | 5.6 |
| 2015 | 25.0°C | 19.1°C | 13.2°C | 27.8°C | 5.8°C | 47 mm | 75% | 0.5 m/s | 6.5 |
| 2014 | 23.9°C | 18.2°C | 12.5°C | 28.5°C | 4.5°C | 75 mm | 77% | 0.6 m/s | 6.2 |
| 2013 | 21.7°C | 16.4°C | 11.1°C | 27.4°C | 2.3°C | 113 mm | 80% | 0.6 m/s | 5.9 |
| 2012 | 24.4°C | 19.4°C | 14.4°C | 28.9°C | 4.9°C | 106 mm | 79% | 0.5 m/s | 6.1 |
| 2011 | 22.8°C | 17.4°C | 12.0°C | 32.0°C | 0.6°C | 79 mm | 79% | 0.6 m/s | 5.3 |
| 2010 | 24.7°C | 19.2°C | 13.8°C | 29.8°C | 3.4°C | 125 mm | 80% | 0.6 m/s | 5.9 |
| 2009 | 22.6°C | 17.6°C | 12.5°C | 26.1°C | 2.2°C | 188 mm | 83% | 0.6 m/s | 5.3 |
| 2008 | 22.7°C | 16.8°C | 10.9°C | 28.2°C | 5.1°C | 73 mm | 74% | 0.7 m/s | 5.7 |
| 2007 | 26.2°C | 19.1°C | 12.0°C | 32.4°C | 4.4°C | 38 mm | 63% | 0.5 m/s | 6.6 |
| 2006 | 22.3°C | 16.7°C | 11.1°C | 31.9°C | 6.1°C | 88 mm | 76% | 0.6 m/s | 5.7 |
| 2005 | 21.3°C | 15.7°C | 10.2°C | 26.6°C | 2.0°C | 69 mm | 77% | 0.6 m/s | 6.4 |
| 2004 | 25.0°C | 19.6°C | 14.2°C | 29.1°C | 1.9°C | 118 mm | 79% | 0.6 m/s | 5.5 |
| 2003 | 22.3°C | 17.7°C | 13.0°C | 26.8°C | 8.3°C | 188 mm | 84% | 0.7 m/s | 4.9 |
| 2002 | 22.8°C | 16.5°C | 10.3°C | 27.9°C | 1.1°C | 101 mm | 76% | 0.6 m/s | 5.4 |
| 2001 | 23.9°C | 17.9°C | 11.8°C | 28.9°C | 6.7°C | 92 mm | 73% | 0.6 m/s | 5.5 |
| 2000 | 24.6°C | 18.7°C | 12.8°C | 28.4°C | 6.5°C | 107 mm | 75% | 0.7 m/s | 5.8 |
| 1999 | 23.1°C | 17.0°C | 11.0°C | 26.9°C | 2.6°C | 102 mm | 75% | 0.6 m/s | 6.7 |
| 1998 | 23.9°C | 19.1°C | 14.2°C | 29.5°C | 7.6°C | 112 mm | 82% | 0.6 m/s | 5.5 |
| 1997 | 20.6°C | 14.4°C | 8.3°C | 25.9°C | 2.7°C | 120 mm | 77% | 0.7 m/s | 5.8 |
| 1996 | 23.5°C | 18.2°C | 12.8°C | 30.5°C | 1.7°C | 145 mm | 82% | 0.6 m/s | 5.9 |
| 1995 | 23.4°C | 17.7°C | 12.0°C | 27.8°C | 5.2°C | 123 mm | 76% | 0.6 m/s | 5.3 |
| 1994 | 21.0°C | 14.9°C | 8.8°C | 26.5°C | 2.7°C | 69 mm | 78% | 0.6 m/s | 6.1 |
| 1993 | 22.6°C | 17.3°C | 12.0°C | 26.2°C | 6.1°C | 84 mm | 79% | 0.6 m/s | 5.5 |
| 1992 | 20.4°C | 15.3°C | 10.2°C | 25.9°C | 2.9°C | 98 mm | 80% | 0.5 m/s | 5.1 |
| 1991 | 24.7°C | 19.6°C | 14.5°C | 28.7°C | 6.5°C | 121 mm | 82% | 0.5 m/s | 5.5 |
| 1990 | 21.6°C | 16.4°C | 11.2°C | 26.4°C | 3.0°C | 155 mm | 80% | 0.6 m/s | 5 |
| 1989 ❄️ | 20.0°C | 14.4°C | 8.8°C | 27.0°C | -0.5°C | 141 mm | 80% | 0.7 m/s | 5 |
| 1988 | 23.0°C | 16.6°C | 10.1°C | 30.7°C | 2.8°C | 74 mm | 68% | 0.7 m/s | 6.2 |
| 1987 | 24.7°C | 19.4°C | 14.1°C | 29.7°C | 6.2°C | 102 mm | 79% | 0.5 m/s | 6.2 |
| 1986 | 24.4°C | 18.0°C | 11.7°C | 28.2°C | 0.2°C | 102 mm | 71% | 0.6 m/s | 5.3 |
| 1985 | 23.9°C | 17.6°C | 11.2°C | 29.9°C | 5.2°C | 69 mm | 72% | 0.6 m/s | 5.3 |
| 1984 🌧️ | 21.1°C | 15.3°C | 9.4°C | 27.0°C | 2.3°C | 230 mm | 80% | 0.7 m/s | 5.1 |
| 1983 | 21.6°C | 15.7°C | 9.8°C | 26.3°C | 1.3°C | 169 mm | 78% | 0.7 m/s | — |
| 1982 | 24.2°C | 18.8°C | 13.4°C | 28.0°C | 5.5°C | 114 mm | 78% | 0.5 m/s | — |
| 1981 | 22.1°C | 15.9°C | 9.7°C | 27.3°C | 3.5°C | 127 mm | 72% | 0.6 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 23.1°C with lows near 11.9°C (mean 17.5°C), based on 45 years of NASA POWER data.
May averages 115 mm of rainfall in Morristown, a relatively wet time of year. The wettest on record was 230 mm in 1984.
The hottest May reached 32.4°C in 2007. The coldest dipped to -0.5°C in 1989.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 1.2°C. Daytime highs moved from 22.6°C to 23.3°C and overnight lows from 10.7°C to 12.5°C over the same span.
May is one of the warmer months of the year in Morristown and a relatively wet time of year, so plan for around 23.1°C daytime highs and 11.9°C at night.
Not quite — May is the 8th coolest month in Morristown, averaging 17.5°C.
For May in Morristown, pack light layers you can adjust through the day, with typical highs of 23.1°C and lows of 11.9°C. Bring an umbrella or light rain jacket too.
Relative humidity in May averages 78% — quite humid.
Average wind speed in May is 0.6 m/s. The windiest May on record averaged 0.7 m/s (1983).
The wettest May on record was 1984 with 230 mm. On average, May sees 115 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 Morristown 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.
