May is one of the cooler months of the year in Blenheim, with average highs near 12.9°C and lows around 5.6°C (mean 9.3°C). It is about average for rainfall, averaging 80 mm of rainfall and 87% relative humidity across the period.
May is one of the cooler months of the year in Blenheim. Across 45 years of records, the warmest May in Blenheim was 2007 — when the month averaged 10.9°C — while the coldest was 1992 at 6.4°C. Typical May days reach 12.9°C with nights near 5.6°C. The long-term trend is warming, about 0.2°C per decade.
May is about average for rainfall in Blenheim, averaging 80 mm of rainfall. The wettest May on record was 1981 with 181 mm, while the driest was 2002 at 29 mm.
Relative humidity in Blenheim during May averages 87%. The most humid May was 2023 at 93%, and the least humid was 1988 at 81%.
May receives about 2.2 kWh/m²/day of solar energy in Blenheim. The sunniest Mays were 1991, 2008 and 2024 at 2.4 kWh/m²/day, and the cloudiest was 2023 at 1.8.
Average wind speed in Blenheim during May is 2.1 m/s. The windiest May was 1983 at 2.9 m/s, while the calmest was 1991 at 1.5 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 8.8°C | 9.0°C | 9.4°C | 9.4°C | 9.8°C | +1°C |
| Avg High | 12.6°C | 12.8°C | 13.1°C | 13.0°C | 13.3°C | +0.7°C |
| Avg Low | 5.1°C | 5.3°C | 5.6°C | 5.9°C | 6.3°C | +1.2°C |
| Avg Rain | 88 mm | 75 mm | 59 mm | 89 mm | 100 mm | +12 mm |
May temperatures in Blenheim have risen by about 1.2°C between 1981–1985 and 2021–2025.
May has ranged from a record low of -1°C (1992) to a record high of 19.9°C (2002).
Rainfall in May is about average for rainfall, averaging 80 mm, with a wettest year of 181 mm.
A good time to visit Blenheim
May is a good time to visit Blenheim, with days averaging 12.9°C and nights around 5.6°C (mean 9.3°C, cooler than Blenheim's yearly average) and higher 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 | 13.4°C | 9.7°C | 6.1°C | 16.5°C | 3.3°C | 117 mm | 90% | 2.2 m/s | 2.1 |
| 2024 | 12.1°C | 8.2°C | 4.3°C | 15.9°C | -0.1°C | 49 mm | 86% | 1.7 m/s | 2.4 |
| 2023 | 13.5°C | 10.8°C | 8.1°C | 17.1°C | 1.6°C | 140 mm | 93% | 2 m/s | 1.8 |
| 2022 | 14.4°C | 10.7°C | 6.9°C | 18.8°C | 1.6°C | 81 mm | 89% | 1.9 m/s | 2.2 |
| 2021 | 13.0°C | 9.7°C | 6.3°C | 18.7°C | 3.1°C | 131 mm | 88% | 2.2 m/s | 2.1 |
| 2020 | 13.3°C | 9.7°C | 6.1°C | 18.1°C | 1.7°C | 81 mm | 88% | 1.8 m/s | 2.1 |
| 2019 | 14.5°C | 10.8°C | 7.0°C | 17.5°C | 2.9°C | 70 mm | 88% | 2.2 m/s | 2.3 |
| 2018 | 12.0°C | 8.8°C | 5.6°C | 17.4°C | 0.8°C | 105 mm | 90% | 2.2 m/s | 2 |
| 2017 | 12.0°C | 8.6°C | 5.2°C | 15.6°C | 1.1°C | 96 mm | 90% | 2 m/s | 2.2 |
| 2016 | 14.1°C | 10.7°C | 7.3°C | 19.8°C | 2.5°C | 120 mm | 87% | 2.5 m/s | 2 |
| 2015 | 12.8°C | 8.8°C | 4.9°C | 17.3°C | -0.8°C | 51 mm | 87% | 2.2 m/s | 2.3 |
| 2014 | 12.9°C | 9.2°C | 5.5°C | 16.5°C | -0.3°C | 56 mm | 89% | 2.3 m/s | 2.2 |
| 2013 | 12.7°C | 9.2°C | 5.8°C | 18.0°C | 0.3°C | 85 mm | 87% | 1.9 m/s | 2.2 |
| 2012 | 12.3°C | 8.4°C | 4.5°C | 14.6°C | 0.1°C | 38 mm | 85% | 1.9 m/s | 2.3 |
| 2011 | 14.1°C | 10.7°C | 7.3°C | 17.1°C | 1.0°C | 132 mm | 89% | 2.1 m/s | 1.9 |
| 2010 | 12.6°C | 9.2°C | 5.9°C | 18.2°C | 0.1°C | 136 mm | 88% | 1.9 m/s | 1.9 |
| 2009 | 10.3°C | 6.8°C | 3.2°C | 14.8°C | 0.4°C | 66 mm | 85% | 2.6 m/s | 2.2 |
| 2008 | 11.5°C | 7.8°C | 4.2°C | 14.7°C | 0.3°C | 38 mm | 87% | 1.9 m/s | 2.4 |
| 2007 🔥 | 15.2°C | 10.9°C | 6.6°C | 18.7°C | 2.2°C | 65 mm | 86% | 2.1 m/s | 2.2 |
| 2006 | 12.9°C | 9.4°C | 5.8°C | 16.2°C | 0.8°C | 77 mm | 87% | 1.7 m/s | 2.1 |
| 2005 | 13.2°C | 9.4°C | 5.6°C | 16.5°C | 0.1°C | 106 mm | 88% | 2.2 m/s | 2.2 |
| 2004 | 12.5°C | 9.7°C | 6.8°C | 16.7°C | 3.0°C | 68 mm | 90% | 2.3 m/s | 2 |
| 2003 | 13.9°C | 10.0°C | 6.1°C | 17.3°C | 1.7°C | 53 mm | 86% | 2.2 m/s | 2.1 |
| 2002 | 13.9°C | 9.9°C | 5.9°C | 19.9°C | 0.0°C | 29 mm | 82% | 2.3 m/s | 2.1 |
| 2001 | 13.3°C | 9.7°C | 6.0°C | 17.9°C | -0.3°C | 40 mm | 85% | 2.1 m/s | 2 |
| 2000 | 13.9°C | 10.0°C | 6.1°C | 19.3°C | 1.0°C | 47 mm | 87% | 2 m/s | 2.1 |
| 1999 | 14.7°C | 10.8°C | 6.9°C | 17.6°C | 2.6°C | 57 mm | 85% | 2.2 m/s | 2.2 |
| 1998 | 13.8°C | 9.9°C | 6.0°C | 17.8°C | 1.7°C | 42 mm | 84% | 1.8 m/s | 2.1 |
| 1997 | 13.5°C | 10.0°C | 6.6°C | 18.4°C | 3.1°C | 57 mm | 88% | 1.9 m/s | 2.1 |
| 1996 | 12.4°C | 8.5°C | 4.7°C | 16.5°C | -0.2°C | 65 mm | 86% | 1.9 m/s | 2.2 |
| 1995 | 12.4°C | 9.1°C | 5.7°C | 16.0°C | 1.0°C | 119 mm | 90% | 2.1 m/s | 2.2 |
| 1994 | 12.4°C | 8.9°C | 5.3°C | 16.3°C | 1.1°C | 81 mm | 86% | 2.4 m/s | 2.2 |
| 1993 | 12.4°C | 8.8°C | 5.2°C | 15.7°C | 0.9°C | 137 mm | 90% | 1.9 m/s | 2.2 |
| 1992 ❄️ | 9.9°C | 6.4°C | 2.9°C | 14.6°C | -1.0°C | 81 mm | 87% | 2.1 m/s | 2.3 |
| 1991 | 12.8°C | 8.6°C | 4.4°C | 15.6°C | 2.0°C | 33 mm | 86% | 1.5 m/s | 2.4 |
| 1990 | 13.2°C | 9.0°C | 4.9°C | 17.3°C | 1.1°C | 80 mm | 87% | 2.2 m/s | 2.2 |
| 1989 | 13.3°C | 9.5°C | 5.8°C | 17.7°C | 0.3°C | 74 mm | 86% | 1.8 m/s | 2.1 |
| 1988 | 13.0°C | 8.6°C | 4.2°C | 18.0°C | -0.4°C | 91 mm | 81% | 1.9 m/s | 2.2 |
| 1987 | 12.8°C | 9.1°C | 5.4°C | 16.4°C | 2.8°C | 155 mm | 89% | 1.9 m/s | 2.1 |
| 1986 | 13.3°C | 9.4°C | 5.4°C | 17.2°C | 1.3°C | 59 mm | 87% | 2.1 m/s | 2.3 |
| 1985 | 11.9°C | 8.7°C | 5.4°C | 18.4°C | 2.2°C | 51 mm | 88% | 2.1 m/s | 2.2 |
| 1984 | 11.9°C | 8.1°C | 4.3°C | 18.0°C | -0.3°C | 74 mm | 85% | 2 m/s | 2.2 |
| 1983 | 11.8°C | 8.1°C | 4.5°C | 16.3°C | 1.2°C | 48 mm | 85% | 2.9 m/s | — |
| 1982 | 13.1°C | 9.2°C | 5.2°C | 15.5°C | 2.2°C | 56 mm | 84% | 2.6 m/s | — |
| 1981 🌧️ | 12.3°C | 8.8°C | 5.3°C | 17.0°C | 1.5°C | 181 mm | 88% | 2.1 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 12.9°C with lows near 5.6°C (mean 9.3°C), based on 45 years of NASA POWER data.
May averages 80 mm of rainfall in Blenheim, about average for rainfall. The wettest on record was 181 mm in 1981.
The hottest May reached 19.9°C in 2002. The coldest dipped to -1°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 12.2°C to 13.3°C and overnight lows from 4.9°C to 6.3°C over the same span.
May is one of the cooler months of the year in Blenheim and about average for rainfall, so plan for around 12.9°C daytime highs and 5.6°C at night.
Not quite — May is the 5th coolest month in Blenheim, averaging 9.3°C.
For May in Blenheim, pack warm layers and a jacket for chilly mornings, with typical highs of 12.9°C and lows of 5.6°C. Bring an umbrella or light rain jacket too.
Relative humidity in May averages 87% — quite humid.
Average wind speed in May is 2.1 m/s. The windiest May on record averaged 2.9 m/s (1983).
The wettest May on record was 1981 with 181 mm. On average, May sees 80 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 Blenheim 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.
