May is one of the warmer months of the year in Waterbury, with average highs near 19.8°C and lows around 8.4°C (mean 14.1°C). It is about average for rainfall, averaging 106 mm of rainfall and 78% relative humidity across the period.
May is one of the warmer months of the year in Waterbury. Across 45 years of records, the warmest Mays in Waterbury were 1991, 2012 and 2015 — when the month averaged 16.6°C — while the coldest were 1997 and 2005 at 11.6°C. Typical May days reach 19.8°C with nights near 8.4°C. The long-term trend is warming, about 0.3°C per decade.
May is about average for rainfall in Waterbury, averaging 106 mm of rainfall. The wettest May on record was 1984 with 274 mm, while the driest were 1986 and 2015 at 39 mm.
Relative humidity in Waterbury during May averages 78%. The most humid Mays were 1983 and 1989 at 84%, and the least humid was 2023 at 71%.
May receives about 5.4 kWh/m²/day of solar energy in Waterbury. The sunniest May was 2023 at 6.8 kWh/m²/day, and the cloudiest was 1984 at 4.1.
Average wind speed in Waterbury during May is 0.1 m/s. The windiest Mays were 2013 and 2023 at 0.2 m/s, while the calmest were 2022, 2024 and 2025, among others at 0.1 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 13.8°C | 13.6°C | 13.8°C | 15.1°C | 14.5°C | +0.7°C |
| Avg High | 19.6°C | 19.4°C | 19.5°C | 20.7°C | 20.2°C | +0.6°C |
| Avg Low | 8.0°C | 7.7°C | 8.0°C | 9.5°C | 8.9°C | +0.9°C |
| Avg Rain | 129 mm | 101 mm | 97 mm | 98 mm | 109 mm | -20 mm |
May temperatures in Waterbury have risen by about 1.2°C between 1981–1985 and 2021–2025.
May has ranged from a record low of -1.4°C (1992) to a record high of 31.7°C (2022).
Rainfall in May is about average for rainfall, averaging 106 mm, with a wettest year of 274 mm.
A good time to visit Waterbury
May is a good time to visit Waterbury, with days averaging 19.8°C and nights around 8.4°C (mean 14.1°C, warmer than Waterbury'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 | 19.7°C | 14.7°C | 9.7°C | 25.5°C | 4.3°C | 186 mm | 81% | 0.1 m/s | 4.5 |
| 2024 | 21.4°C | 16.0°C | 10.7°C | 29.0°C | 4.0°C | 129 mm | 81% | 0.1 m/s | 5.5 |
| 2023 | 20.0°C | 13.8°C | 7.6°C | 27.0°C | 0.3°C | 61 mm | 71% | 0.2 m/s | 6.8 |
| 2022 | 21.3°C | 15.4°C | 9.6°C | 31.7°C | 2.3°C | 78 mm | 76% | 0.1 m/s | 5.5 |
| 2021 | 19.9°C | 14.3°C | 8.6°C | 28.6°C | 2.2°C | 138 mm | 74% | 0.1 m/s | 5.6 |
| 2020 | 18.7°C | 12.9°C | 7.0°C | 25.9°C | -0.1°C | 61 mm | 75% | 0.1 m/s | 6.2 |
| 2019 | 19.2°C | 14.0°C | 8.9°C | 27.3°C | 3.1°C | 129 mm | 81% | 0.1 m/s | 5 |
| 2018 | 22.1°C | 16.4°C | 10.6°C | 30.7°C | 3.0°C | 74 mm | 79% | 0.1 m/s | 5.2 |
| 2017 | 18.6°C | 13.4°C | 8.3°C | 29.9°C | 2.3°C | 134 mm | 79% | 0.1 m/s | 4.9 |
| 2016 | 19.5°C | 14.1°C | 8.8°C | 30.0°C | 2.4°C | 82 mm | 78% | 0.1 m/s | 5.1 |
| 2015 | 23.0°C | 16.6°C | 10.3°C | 27.4°C | 4.2°C | 39 mm | 74% | 0.1 m/s | 6.1 |
| 2014 | 19.8°C | 14.4°C | 9.1°C | 26.1°C | 3.8°C | 103 mm | 79% | 0.1 m/s | 5.4 |
| 2013 | 20.2°C | 14.2°C | 8.3°C | 30.9°C | 1.1°C | 115 mm | 78% | 0.2 m/s | 5.6 |
| 2012 | 21.9°C | 16.6°C | 11.3°C | 30.3°C | 5.3°C | 103 mm | 81% | 0.1 m/s | 4.9 |
| 2011 | 20.8°C | 15.3°C | 9.8°C | 28.8°C | 3.6°C | 130 mm | 83% | 0.1 m/s | 5 |
| 2010 | 21.5°C | 15.5°C | 9.4°C | 30.7°C | 1.0°C | 68 mm | 77% | 0.1 m/s | 6 |
| 2009 | 20.0°C | 14.5°C | 8.9°C | 26.8°C | 2.7°C | 103 mm | 78% | 0.1 m/s | 5 |
| 2008 | 18.4°C | 12.7°C | 7.0°C | 25.4°C | 0.2°C | 73 mm | 76% | 0.1 m/s | 5.5 |
| 2007 | 21.3°C | 14.9°C | 8.5°C | 30.4°C | 1.5°C | 43 mm | 76% | 0.1 m/s | 6.6 |
| 2006 | 19.3°C | 14.0°C | 8.6°C | 28.8°C | 3.0°C | 154 mm | 79% | 0.1 m/s | 5.1 |
| 2005 | 17.0°C | 11.6°C | 6.2°C | 22.7°C | 0.5°C | 65 mm | 78% | 0.1 m/s | 5.5 |
| 2004 | 21.3°C | 15.4°C | 9.4°C | 27.8°C | 1.6°C | 94 mm | 81% | 0.1 m/s | 5.4 |
| 2003 | 18.2°C | 12.8°C | 7.5°C | 24.0°C | 2.3°C | 126 mm | 81% | 0.1 m/s | 4.5 |
| 2002 | 19.1°C | 13.0°C | 6.8°C | 26.4°C | 0.4°C | 119 mm | 72% | 0.1 m/s | 5.7 |
| 2001 | 20.7°C | 14.7°C | 8.8°C | 30.8°C | 1.7°C | 88 mm | 73% | 0.1 m/s | 5.5 |
| 2000 | 19.8°C | 14.1°C | 8.5°C | 29.2°C | 0.9°C | 106 mm | 79% | 0.1 m/s | 5.2 |
| 1999 | 20.9°C | 14.8°C | 8.6°C | 29.5°C | 2.3°C | 97 mm | 73% | 0.1 m/s | 5.7 |
| 1998 | 20.9°C | 15.3°C | 9.8°C | 26.9°C | 1.3°C | 170 mm | 82% | 0.1 m/s | 5.7 |
| 1997 ❄️ | 17.2°C | 11.6°C | 6.0°C | 25.6°C | 0.2°C | 86 mm | 76% | 0.1 m/s | 5.5 |
| 1996 | 18.1°C | 12.4°C | 6.6°C | 28.5°C | -1.3°C | 79 mm | 78% | 0.1 m/s | 5.2 |
| 1995 | 18.4°C | 12.9°C | 7.4°C | 25.2°C | 2.0°C | 68 mm | 76% | 0.1 m/s | 4.9 |
| 1994 | 18.7°C | 12.7°C | 6.8°C | 28.0°C | 1.6°C | 92 mm | 78% | 0.1 m/s | 5.6 |
| 1993 | 20.5°C | 14.5°C | 8.5°C | 27.1°C | 5.6°C | 41 mm | 77% | 0.1 m/s | 5.7 |
| 1992 | 19.6°C | 13.0°C | 6.5°C | 29.3°C | -1.4°C | 80 mm | 75% | 0.1 m/s | 5.5 |
| 1991 🔥 | 22.5°C | 16.6°C | 10.7°C | 30.8°C | 4.7°C | 109 mm | 78% | 0.1 m/s | 6.1 |
| 1990 | 17.2°C | 11.8°C | 6.5°C | 22.8°C | 1.7°C | 188 mm | 80% | 0.1 m/s | 5 |
| 1989 | 19.2°C | 13.7°C | 8.1°C | 25.7°C | 2.2°C | 269 mm | 84% | 0.1 m/s | 4.8 |
| 1988 | 19.7°C | 14.1°C | 8.4°C | 27.3°C | 2.7°C | 97 mm | 82% | 0.1 m/s | 5.2 |
| 1987 | 19.5°C | 13.7°C | 7.8°C | 28.6°C | 0.9°C | 57 mm | 81% | 0.1 m/s | 5.3 |
| 1986 | 20.9°C | 14.9°C | 8.8°C | 28.3°C | -1.0°C | 39 mm | 76% | 0.1 m/s | 6.2 |
| 1985 | 20.7°C | 14.7°C | 8.6°C | 27.3°C | -0.5°C | 126 mm | 74% | 0.1 m/s | 5.7 |
| 1984 🌧️ | 17.4°C | 12.2°C | 7.0°C | 24.8°C | 1.0°C | 274 mm | 83% | 0.1 m/s | 4.1 |
| 1983 | 17.5°C | 12.2°C | 6.8°C | 23.7°C | 0.0°C | 134 mm | 84% | 0.1 m/s | — |
| 1982 | 20.7°C | 14.8°C | 8.8°C | 25.6°C | 3.9°C | 77 mm | 77% | 0.1 m/s | — |
| 1981 | 20.6°C | 14.2°C | 7.8°C | 27.3°C | 1.2°C | 88 mm | 73% | 0.1 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 19.8°C with lows near 8.4°C (mean 14.1°C), based on 45 years of NASA POWER data.
May averages 106 mm of rainfall in Waterbury, about average for rainfall. The wettest on record was 274 mm in 1984.
The hottest May reached 31.7°C in 2022. The coldest dipped to -1.4°C in 1992.
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 19.4°C to 20.5°C and overnight lows from 7.8°C to 9.2°C over the same span.
May is one of the warmer months of the year in Waterbury and about average for rainfall, so plan for around 19.8°C daytime highs and 8.4°C at night.
Not quite — May is the 8th coolest month in Waterbury, averaging 14.1°C.
For May in Waterbury, pack light layers you can adjust through the day, with typical highs of 19.8°C and lows of 8.4°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 0.2 m/s (2013).
The wettest May on record was 1984 with 274 mm. On average, May sees 106 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 Waterbury 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.
