May is one of the cooler months of the year in Hamilton, with average highs near 15.9°C and lows around 6.7°C (mean 11.3°C). It is about average for rainfall, averaging 55 mm of rainfall and 81% relative humidity across the period.
May is one of the cooler months of the year in Hamilton. Across 45 years of records, the warmest May in Hamilton was 1988 — when the month averaged 13.1°C — while the coldest was 2011 at 9.7°C. Typical May days reach 15.9°C with nights near 6.7°C. The long-term May temperature trend is broadly flat.
May is about average for rainfall in Hamilton, averaging 55 mm of rainfall. The wettest May on record was 1987 with 133 mm, while the driest was 1996 at 10 mm.
Relative humidity in Hamilton during May averages 81%. The most humid May was 1983 at 88%, and the least humid was 2025 at 72%.
May receives about 2.4 kWh/m²/day of solar energy in Hamilton. The sunniest May was 2025 at 2.9 kWh/m²/day, and the cloudiest were 1997, 2011 and 2018, among others at 2.1.
Average wind speed in Hamilton during May is 2.6 m/s. The windiest May was 1994 at 3.5 m/s, while the calmest were 1991 and 2001 at 2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 11.4°C | 11.2°C | 11.5°C | 11.3°C | 11.2°C | -0.2°C |
| Avg High | 15.9°C | 15.8°C | 16.1°C | 15.6°C | 16.1°C | +0.2°C |
| Avg Low | 6.8°C | 6.5°C | 6.8°C | 7.0°C | 6.3°C | -0.5°C |
| Avg Rain | 77 mm | 44 mm | 49 mm | 62 mm | 40 mm | -37 mm |
May temperatures in Hamilton have risen by about 0.5°C between 1981–1985 and 2021–2025.
May has ranged from a record low of 0.3°C (2021) to a record high of 26.4°C (2005).
Rainfall in May is about average for rainfall, averaging 55 mm, with a wettest year of 133 mm.
A good time to visit Hamilton
May is a good time to visit Hamilton, with days averaging 15.9°C and nights around 6.7°C (mean 11.3°C, cooler than Hamilton's yearly average) and moderate rainfall. February and January 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 | 18.0°C | 12.3°C | 6.5°C | 25.1°C | 0.6°C | 17 mm | 72% | 2.5 m/s | 2.9 |
| 2024 | 17.5°C | 11.9°C | 6.2°C | 20.6°C | 2.7°C | 23 mm | 76% | 2.1 m/s | 2.7 |
| 2023 | 15.1°C | 10.7°C | 6.3°C | 20.0°C | 2.5°C | 43 mm | 82% | 2.6 m/s | 2.3 |
| 2022 | 15.7°C | 11.3°C | 6.9°C | 21.4°C | 3.3°C | 44 mm | 83% | 2.5 m/s | 2.3 |
| 2021 | 16.0°C | 11.1°C | 6.2°C | 22.6°C | 0.3°C | 48 mm | 77% | 2.9 m/s | 2.4 |
| 2020 | 14.2°C | 9.9°C | 5.6°C | 19.5°C | 1.5°C | 67 mm | 82% | 2.9 m/s | 2.5 |
| 2019 | 16.3°C | 11.7°C | 7.1°C | 23.0°C | 4.1°C | 72 mm | 80% | 2.9 m/s | 2.4 |
| 2018 | 15.4°C | 11.6°C | 7.7°C | 22.6°C | 3.2°C | 72 mm | 79% | 3 m/s | 2.1 |
| 2017 | 15.1°C | 10.9°C | 6.6°C | 19.9°C | 2.4°C | 51 mm | 82% | 2.4 m/s | 2.3 |
| 2016 | 16.4°C | 12.3°C | 8.1°C | 22.5°C | 1.2°C | 68 mm | 79% | 3.4 m/s | 2.3 |
| 2015 | 15.0°C | 10.8°C | 6.6°C | 22.3°C | 2.8°C | 81 mm | 83% | 3.3 m/s | 2.4 |
| 2014 | 16.6°C | 12.3°C | 8.0°C | 22.7°C | 1.7°C | 63 mm | 83% | 2.5 m/s | 2.3 |
| 2013 | 16.3°C | 11.6°C | 6.9°C | 25.0°C | 3.2°C | 66 mm | 79% | 2.5 m/s | 2.4 |
| 2012 | 15.6°C | 11.2°C | 6.9°C | 22.7°C | 2.2°C | 56 mm | 81% | 2.7 m/s | 2.4 |
| 2011 ❄️ | 13.5°C | 9.7°C | 6.0°C | 18.0°C | 2.9°C | 52 mm | 85% | 2.2 m/s | 2.1 |
| 2010 | 15.9°C | 11.1°C | 6.4°C | 22.1°C | 0.8°C | 43 mm | 82% | 2.2 m/s | 2.4 |
| 2009 | 16.2°C | 11.8°C | 7.4°C | 20.1°C | 4.9°C | 43 mm | 84% | 2.3 m/s | 2.2 |
| 2008 | 16.4°C | 11.4°C | 6.4°C | 21.2°C | 2.7°C | 47 mm | 82% | 2.1 m/s | 2.3 |
| 2007 | 17.1°C | 13.0°C | 8.8°C | 22.1°C | 5.4°C | 111 mm | 82% | 3.4 m/s | 2.3 |
| 2006 | 14.1°C | 9.8°C | 5.4°C | 18.4°C | 2.2°C | 43 mm | 86% | 2.3 m/s | 2.2 |
| 2005 | 17.0°C | 11.8°C | 6.6°C | 26.4°C | 3.3°C | 16 mm | 75% | 2.3 m/s | 2.5 |
| 2004 | 15.4°C | 10.6°C | 5.9°C | 19.6°C | 1.3°C | 41 mm | 82% | 2.8 m/s | 2.4 |
| 2003 | 16.9°C | 11.8°C | 6.7°C | 22.0°C | 2.4°C | 36 mm | 79% | 2.2 m/s | 2.5 |
| 2002 | 17.3°C | 12.3°C | 7.2°C | 26.1°C | 4.1°C | 43 mm | 76% | 2.3 m/s | 2.5 |
| 2001 | 15.8°C | 11.2°C | 6.5°C | 22.4°C | 4.6°C | 31 mm | 83% | 2 m/s | 2.4 |
| 2000 | 15.0°C | 10.9°C | 6.8°C | 20.3°C | 1.7°C | 82 mm | 83% | 3 m/s | 2.3 |
| 1999 | 16.9°C | 12.1°C | 7.2°C | 23.3°C | 1.3°C | 67 mm | 77% | 3 m/s | 2.3 |
| 1998 | 15.8°C | 11.1°C | 6.4°C | 22.0°C | 2.8°C | 29 mm | 82% | 2.4 m/s | 2.3 |
| 1997 | 15.4°C | 11.0°C | 6.7°C | 22.0°C | 2.5°C | 83 mm | 84% | 2.4 m/s | 2.1 |
| 1996 | 16.6°C | 11.5°C | 6.4°C | 23.9°C | 2.0°C | 10 mm | 80% | 2.1 m/s | 2.2 |
| 1995 | 14.2°C | 10.3°C | 6.3°C | 19.8°C | 3.0°C | 46 mm | 86% | 2.5 m/s | 2.3 |
| 1994 | 15.3°C | 10.8°C | 6.4°C | 22.5°C | 2.2°C | 64 mm | 77% | 3.5 m/s | 2.4 |
| 1993 | 16.6°C | 11.4°C | 6.3°C | 24.5°C | 2.0°C | 38 mm | 79% | 2.4 m/s | 2.5 |
| 1992 | 14.6°C | 10.4°C | 6.2°C | 21.6°C | 1.9°C | 65 mm | 85% | 2.2 m/s | 2.3 |
| 1991 | 16.6°C | 11.5°C | 6.3°C | 20.5°C | 3.4°C | 13 mm | 80% | 2 m/s | 2.4 |
| 1990 | 16.4°C | 11.5°C | 6.7°C | 24.9°C | 2.3°C | 21 mm | 77% | 2.7 m/s | 2.5 |
| 1989 | 16.3°C | 12.1°C | 7.9°C | 20.8°C | 3.1°C | 68 mm | 83% | 2.7 m/s | 2.2 |
| 1988 🔥 | 17.4°C | 13.1°C | 8.8°C | 25.8°C | 5.2°C | 87 mm | 82% | 2.3 m/s | 2.2 |
| 1987 🌧️ | 15.2°C | 11.1°C | 6.9°C | 21.8°C | 2.1°C | 133 mm | 84% | 2.9 m/s | 2.1 |
| 1986 | 15.3°C | 11.0°C | 6.6°C | 21.1°C | 4.1°C | 88 mm | 86% | 2.4 m/s | 2.3 |
| 1985 | 16.2°C | 11.3°C | 6.4°C | 25.4°C | 1.6°C | 58 mm | 79% | 2.6 m/s | 2.5 |
| 1984 | 16.3°C | 11.1°C | 6.0°C | 21.8°C | 2.3°C | 35 mm | 78% | 2.5 m/s | 2.6 |
| 1983 | 15.1°C | 10.7°C | 6.4°C | 17.8°C | 0.9°C | 102 mm | 88% | 2.6 m/s | — |
| 1982 | 15.3°C | 10.6°C | 5.8°C | 21.2°C | 1.2°C | 51 mm | 77% | 2.9 m/s | — |
| 1981 | 16.4°C | 11.3°C | 6.3°C | 25.3°C | 0.6°C | 72 mm | 76% | 2.7 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 15.9°C with lows near 6.7°C (mean 11.3°C), based on 45 years of NASA POWER data.
May averages 55 mm of rainfall in Hamilton, about average for rainfall. The wettest on record was 133 mm in 1987.
The hottest May reached 26.4°C in 2005. The coldest dipped to 0.3°C in 2021.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 0.5°C. Daytime highs moved from 15.9°C to 16.5°C and overnight lows from 6.2°C to 6.4°C over the same span.
May is one of the cooler months of the year in Hamilton and about average for rainfall, so plan for around 15.9°C daytime highs and 6.7°C at night.
Not quite — May is the 5th coolest month in Hamilton, averaging 11.3°C.
For May in Hamilton, pack warm layers and a jacket for chilly mornings, with typical highs of 15.9°C and lows of 6.7°C. Bring an umbrella or light rain jacket too.
Relative humidity in May averages 81% — quite humid.
Average wind speed in May is 2.6 m/s. The windiest May on record averaged 3.5 m/s (1994).
The wettest May on record was 1987 with 133 mm. On average, May sees 55 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 Hamilton 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.
