May is one of the warmer months of the year in Chatham, with average highs near 18.5°C and lows around 8.4°C (mean 13.5°C). It is about average for rainfall, averaging 63 mm of rainfall and 74% relative humidity across the period.
May is one of the warmer months of the year in Chatham. Across 45 years of records, the warmest May in Chatham was 1998 — when the month averaged 17.3°C — while the coldest was 1997 at 9.7°C. Typical May days reach 18.5°C with nights near 8.4°C. The long-term trend is warming, about 0.5°C per decade.
May is about average for rainfall in Chatham, averaging 63 mm of rainfall. The wettest May on record was 1989 with 126 mm, while the driest was 2023 at 16 mm.
Relative humidity in Chatham during May averages 74%. The most humid May was 2011 at 82%, and the least humid was 2023 at 60%.
May receives about 5.6 kWh/m²/day of solar energy in Chatham. The sunniest May was 2023 at 6.4 kWh/m²/day, and the cloudiest were 1984 and 2019 at 4.6.
Average wind speed in Chatham during May is 3.4 m/s. The windiest May was 1997 at 4.3 m/s, while the calmest was 1982 at 2.6 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 12.7°C | 13.1°C | 13.0°C | 14.3°C | 14.5°C | +1.8°C |
| Avg High | 17.7°C | 18.3°C | 18.0°C | 19.3°C | 19.7°C | +2°C |
| Avg Low | 7.7°C | 8.0°C | 8.0°C | 9.4°C | 9.3°C | +1.6°C |
| Avg Rain | 80 mm | 40 mm | 72 mm | 78 mm | 34 mm | -46 mm |
May temperatures in Chatham have risen by about 2.7°C between 1981–1985 and 2021–2025.
May has ranged from a record low of -2°C (2020) to a record high of 30.5°C (2018).
Rainfall in May is about average for rainfall, averaging 63 mm, with a wettest year of 126 mm.
A good time to visit Chatham
May is a good time to visit Chatham, with days averaging 18.5°C and nights around 8.4°C (mean 13.5°C, warmer than Chatham's yearly average) and moderate 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 | 17.9°C | 13.4°C | 8.9°C | 25.5°C | 2.9°C | 57 mm | 74% | 3.8 m/s | 5.2 |
| 2024 | 22.1°C | 16.9°C | 11.6°C | 28.2°C | 6.1°C | 46 mm | 70% | 3.2 m/s | 5.9 |
| 2023 | 20.5°C | 14.4°C | 8.3°C | 29.1°C | 2.5°C | 16 mm | 60% | 3 m/s | 6.4 |
| 2022 | 20.6°C | 15.5°C | 10.4°C | 28.8°C | 3.4°C | 36 mm | 69% | 3.6 m/s | 5.7 |
| 2021 | 19.9°C | 14.4°C | 8.9°C | 29.2°C | 1.0°C | 16 mm | 60% | 3.3 m/s | 5.7 |
| 2020 | 17.1°C | 12.4°C | 7.7°C | 28.0°C | -2.0°C | 31 mm | 74% | 3.8 m/s | 5.7 |
| 2019 | 17.6°C | 12.4°C | 7.2°C | 24.0°C | 3.2°C | 75 mm | 81% | 3.4 m/s | 4.6 |
| 2018 | 21.6°C | 16.1°C | 10.5°C | 30.5°C | 3.9°C | 70 mm | 77% | 3.2 m/s | 5.8 |
| 2017 | 17.1°C | 12.8°C | 8.4°C | 25.6°C | 0.3°C | 105 mm | 77% | 3.9 m/s | 5.4 |
| 2016 | 18.6°C | 13.8°C | 8.9°C | 27.2°C | 2.8°C | 38 mm | 74% | 3.1 m/s | 6 |
| 2015 | 20.1°C | 15.0°C | 10.0°C | 25.8°C | 2.7°C | 88 mm | 76% | 3.1 m/s | 5.4 |
| 2014 | 18.6°C | 13.7°C | 8.9°C | 24.6°C | 2.2°C | 85 mm | 77% | 3 m/s | 5.4 |
| 2013 | 19.2°C | 14.3°C | 9.4°C | 24.8°C | 0.4°C | 82 mm | 75% | 3.6 m/s | 6.1 |
| 2012 | 21.2°C | 16.0°C | 10.8°C | 28.4°C | 5.5°C | 75 mm | 72% | 2.8 m/s | 6.2 |
| 2011 | 18.3°C | 13.8°C | 9.4°C | 28.1°C | 2.2°C | 92 mm | 82% | 3.3 m/s | 4.9 |
| 2010 | 20.3°C | 15.5°C | 10.7°C | 29.2°C | 1.5°C | 67 mm | 73% | 3.6 m/s | 5.7 |
| 2009 | 18.9°C | 13.5°C | 8.1°C | 24.3°C | 3.0°C | 46 mm | 70% | 3.5 m/s | 6 |
| 2008 | 17.2°C | 12.1°C | 7.0°C | 23.7°C | 2.1°C | 43 mm | 71% | 3.7 m/s | 5.5 |
| 2007 | 20.4°C | 14.7°C | 9.1°C | 30.0°C | 2.7°C | 46 mm | 66% | 3.2 m/s | 5.9 |
| 2006 | 18.8°C | 14.2°C | 9.5°C | 30.3°C | 3.6°C | 78 mm | 72% | 3.4 m/s | 5.7 |
| 2005 | 17.5°C | 12.4°C | 7.3°C | 24.3°C | 0.7°C | 32 mm | 67% | 3.1 m/s | 5.6 |
| 2004 | 18.4°C | 13.4°C | 8.4°C | 24.9°C | 0.2°C | 118 mm | 81% | 3.5 m/s | 5 |
| 2003 | 16.6°C | 11.8°C | 6.9°C | 21.6°C | 1.9°C | 82 mm | 79% | 3.7 m/s | 4.9 |
| 2002 | 15.0°C | 10.1°C | 5.2°C | 24.3°C | -0.2°C | 67 mm | 76% | 3.9 m/s | 5.3 |
| 2001 | 18.1°C | 13.4°C | 8.7°C | 24.0°C | 1.1°C | 86 mm | 78% | 3.5 m/s | 5.2 |
| 2000 | 18.9°C | 14.3°C | 9.7°C | 24.7°C | 4.7°C | 117 mm | 78% | 3.7 m/s | 5 |
| 1999 | 19.8°C | 14.6°C | 9.5°C | 26.9°C | 5.2°C | 45 mm | 71% | 3.5 m/s | 5.9 |
| 1998 🔥 | 22.6°C | 17.3°C | 12.0°C | 29.4°C | 6.9°C | 24 mm | 70% | 3.2 m/s | 6 |
| 1997 ❄️ | 14.5°C | 9.7°C | 4.9°C | 20.6°C | 0.9°C | 59 mm | 73% | 4.3 m/s | 4.8 |
| 1996 | 16.5°C | 11.6°C | 6.7°C | 25.4°C | 0.1°C | 42 mm | 73% | 3.6 m/s | 5.3 |
| 1995 | 17.8°C | 12.8°C | 7.7°C | 23.1°C | 2.4°C | 45 mm | 70% | 3.4 m/s | 5.1 |
| 1994 | 17.2°C | 11.5°C | 5.9°C | 27.7°C | 0.8°C | 29 mm | 70% | 3.5 m/s | 5.9 |
| 1993 | 17.9°C | 12.7°C | 7.6°C | 24.6°C | 3.2°C | 26 mm | 72% | 3.4 m/s | 5.3 |
| 1992 | 18.3°C | 12.6°C | 6.9°C | 25.8°C | 2.1°C | 29 mm | 69% | 3.1 m/s | 5.9 |
| 1991 | 21.4°C | 16.5°C | 11.7°C | 27.7°C | 1.6°C | 45 mm | 76% | 3.2 m/s | 5.5 |
| 1990 | 16.7°C | 11.9°C | 7.1°C | 21.8°C | 2.3°C | 61 mm | 72% | 3.9 m/s | 5.6 |
| 1989 🌧️ | 16.7°C | 12.1°C | 7.5°C | 23.8°C | 0.8°C | 126 mm | 77% | 3.3 m/s | 5.3 |
| 1988 | 19.3°C | 13.7°C | 8.1°C | 28.5°C | 3.2°C | 39 mm | 73% | 3.2 m/s | 6.3 |
| 1987 | 19.5°C | 14.1°C | 8.7°C | 26.9°C | 1.2°C | 65 mm | 75% | 3.1 m/s | 6.2 |
| 1986 | 17.9°C | 13.2°C | 8.5°C | 25.9°C | -1.6°C | 91 mm | 81% | 3.3 m/s | 5.8 |
| 1985 | 18.4°C | 13.3°C | 8.3°C | 24.2°C | 3.4°C | 69 mm | 77% | 3.6 m/s | 6.3 |
| 1984 | 14.8°C | 10.3°C | 5.8°C | 21.6°C | -0.3°C | 105 mm | 79% | 3.8 m/s | 4.6 |
| 1983 | 15.3°C | 10.4°C | 5.5°C | 20.0°C | -1.8°C | 116 mm | 77% | 3.9 m/s | — |
| 1982 | 19.9°C | 14.7°C | 9.5°C | 24.8°C | 3.0°C | 52 mm | 79% | 2.6 m/s | — |
| 1981 | 17.2°C | 12.3°C | 7.3°C | 23.9°C | 0.6°C | 58 mm | 74% | 3.2 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 18.5°C with lows near 8.4°C (mean 13.5°C), based on 45 years of NASA POWER data.
May averages 63 mm of rainfall in Chatham, about average for rainfall. The wettest on record was 126 mm in 1989.
The hottest May reached 30.5°C in 2018. The coldest dipped to -2°C in 2020.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 2.7°C. Daytime highs moved from 17.1°C to 20.2°C and overnight lows from 7.3°C to 9.6°C over the same span.
May is one of the warmer months of the year in Chatham and about average for rainfall, so plan for around 18.5°C daytime highs and 8.4°C at night.
Not quite — May is the 8th coolest month in Chatham, averaging 13.5°C.
For May in Chatham, pack light layers you can adjust through the day, with typical highs of 18.5°C and lows of 8.4°C. Bring an umbrella or light rain jacket too.
Relative humidity in May averages 74% — moderately humid.
Average wind speed in May is 3.4 m/s. The windiest May on record averaged 4.3 m/s (1997).
The wettest May on record was 1989 with 126 mm. On average, May sees 63 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 Chatham 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.
