May is one of the cooler months of the year in Northam, with average highs near 21.4°C and lows around 9.2°C (mean 15.3°C). It is a relatively wet time of year, averaging 54 mm of rainfall and 67% relative humidity across the period.
May is one of the cooler months of the year in Northam. Across 45 years of records, the warmest May in Northam was 2024 — when the month averaged 18.1°C — while the coldest was 1987 at 13.1°C. Typical May days reach 21.4°C with nights near 9.2°C. The long-term trend is warming, about 0.2°C per decade.
May is a relatively wet time of year in Northam, averaging 54 mm of rainfall. The wettest May on record was 1999 with 125 mm, while the driest was 2019 at 9 mm.
Relative humidity in Northam during May averages 67%. The most humid May was 2014 at 81%, and the least humid was 2018 at 52%.
May receives about 3.4 kWh/m²/day of solar energy in Northam. The sunniest Mays were 2000 and 2009 at 3.8 kWh/m²/day, and the cloudiest were 1999, 2005 and 2014 at 2.9.
Average wind speed in Northam during May is 2.8 m/s. The windiest May was 1981 at 3.6 m/s, while the calmest were 2008 and 2016 at 2.2 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 14.9°C | 15.4°C | 15.5°C | 15.1°C | 16.0°C | +1.1°C |
| Avg High | 20.8°C | 21.2°C | 21.7°C | 21.3°C | 22.4°C | +1.6°C |
| Avg Low | 8.9°C | 9.5°C | 9.3°C | 9.0°C | 9.7°C | +0.8°C |
| Avg Rain | 67 mm | 60 mm | 49 mm | 40 mm | 55 mm | -12 mm |
May temperatures in Northam have risen by about 1.2°C between 1981–1985 and 2021–2025.
May has ranged from a record low of 2.3°C (2019) to a record high of 32.9°C (2002).
Rainfall in May is a relatively wet time of year, averaging 54 mm, with a wettest year of 125 mm.
A good time to visit Northam
May is a good time to visit Northam, with days averaging 21.4°C and nights around 9.2°C (mean 15.3°C, cooler than Northam's yearly average) and moderate rainfall. November and March 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 | 24.0°C | 17.0°C | 10.1°C | 31.7°C | 3.0°C | 31 mm | 60% | 2.8 m/s | 3.6 |
| 2024 🔥 | 24.3°C | 18.1°C | 11.9°C | 28.0°C | 7.5°C | 36 mm | 57% | 2.7 m/s | 3.3 |
| 2023 | 22.5°C | 15.7°C | 8.9°C | 27.5°C | 3.7°C | 24 mm | 60% | 2.9 m/s | 3.4 |
| 2022 | 21.3°C | 15.1°C | 9.0°C | 26.7°C | 4.2°C | 67 mm | 71% | 2.7 m/s | 3.4 |
| 2021 | 21.1°C | 15.5°C | 9.9°C | 25.9°C | 4.3°C | 88 mm | 71% | 2.6 m/s | 3.1 |
| 2020 | 21.1°C | 14.8°C | 8.5°C | 27.9°C | 4.4°C | 83 mm | 65% | 3.3 m/s | 3.5 |
| 2019 | 21.6°C | 14.6°C | 7.5°C | 28.2°C | 2.3°C | 9 mm | 60% | 2.6 m/s | 3.7 |
| 2018 | 23.0°C | 16.2°C | 9.5°C | 30.7°C | 5.1°C | 39 mm | 52% | 3.2 m/s | 3.7 |
| 2017 | 22.0°C | 15.8°C | 9.7°C | 29.5°C | 4.2°C | 21 mm | 65% | 2.7 m/s | 3.6 |
| 2016 | 19.3°C | 13.5°C | 7.7°C | 25.4°C | 3.6°C | 59 mm | 77% | 2.2 m/s | 3.5 |
| 2015 | 20.6°C | 14.3°C | 8.0°C | 24.4°C | 4.5°C | 27 mm | 65% | 2.9 m/s | 3.7 |
| 2014 | 20.0°C | 15.2°C | 10.4°C | 22.8°C | 4.8°C | 74 mm | 81% | 2.5 m/s | 2.9 |
| 2013 | 20.6°C | 14.9°C | 9.2°C | 26.7°C | 4.7°C | 63 mm | 72% | 2.6 m/s | 3.4 |
| 2012 | 22.4°C | 16.0°C | 9.6°C | 26.3°C | 4.0°C | 24 mm | 64% | 2.6 m/s | 3.6 |
| 2011 | 22.1°C | 16.0°C | 9.9°C | 27.7°C | 6.5°C | 45 mm | 64% | 2.8 m/s | 3.5 |
| 2010 | 21.7°C | 14.9°C | 8.0°C | 29.8°C | 3.4°C | 42 mm | 62% | 2.6 m/s | 3.7 |
| 2009 | 22.7°C | 16.0°C | 9.2°C | 26.5°C | 4.3°C | 31 mm | 55% | 3 m/s | 3.8 |
| 2008 | 22.1°C | 15.9°C | 9.8°C | 29.5°C | 5.4°C | 56 mm | 74% | 2.2 m/s | 3.5 |
| 2007 | 20.0°C | 14.1°C | 8.1°C | 25.8°C | 4.2°C | 34 mm | 73% | 2.5 m/s | 3.5 |
| 2006 | 21.6°C | 14.9°C | 8.3°C | 27.1°C | 3.2°C | 20 mm | 63% | 2.8 m/s | 3.5 |
| 2005 | 22.9°C | 17.2°C | 11.5°C | 28.4°C | 7.6°C | 91 mm | 74% | 3.1 m/s | 2.9 |
| 2004 | 20.1°C | 14.3°C | 8.5°C | 29.1°C | 3.3°C | 82 mm | 69% | 3 m/s | 3.3 |
| 2003 | 22.7°C | 16.6°C | 10.6°C | 29.6°C | 4.8°C | 70 mm | 65% | 3.1 m/s | 3.4 |
| 2002 | 22.9°C | 16.4°C | 10.0°C | 32.9°C | 6.2°C | 26 mm | 67% | 2.8 m/s | 3.4 |
| 2001 | 21.6°C | 15.6°C | 9.7°C | 29.6°C | 4.7°C | 66 mm | 72% | 2.6 m/s | 3 |
| 2000 | 20.7°C | 14.1°C | 7.6°C | 25.7°C | 4.5°C | 16 mm | 65% | 2.5 m/s | 3.8 |
| 1999 🌧️ | 21.4°C | 16.2°C | 11.0°C | 28.7°C | 4.1°C | 125 mm | 74% | 2.9 m/s | 2.9 |
| 1998 | 23.5°C | 17.3°C | 11.1°C | 31.8°C | 5.2°C | 40 mm | 68% | 2.8 m/s | 3.2 |
| 1997 | 20.2°C | 14.8°C | 9.5°C | 27.5°C | 4.0°C | 42 mm | 72% | 3.3 m/s | 3.2 |
| 1996 | 22.8°C | 16.3°C | 9.8°C | 29.7°C | 4.7°C | 36 mm | 58% | 2.9 m/s | 3.4 |
| 1995 | 19.6°C | 13.7°C | 7.9°C | 27.1°C | 3.1°C | 86 mm | 70% | 3.1 m/s | 3.6 |
| 1994 | 22.7°C | 16.6°C | 10.4°C | 30.6°C | 7.7°C | 87 mm | 64% | 2.9 m/s | 3.6 |
| 1993 | 20.2°C | 14.2°C | 8.2°C | 24.5°C | 3.1°C | 79 mm | 72% | 2.7 m/s | 3.4 |
| 1992 | 19.8°C | 14.2°C | 8.5°C | 23.4°C | 3.9°C | 26 mm | 74% | 2.9 m/s | 3.5 |
| 1991 | 21.4°C | 15.4°C | 9.5°C | 27.7°C | 4.0°C | 49 mm | 67% | 3 m/s | 3.2 |
| 1990 | 20.8°C | 14.8°C | 8.8°C | 29.6°C | 4.1°C | 25 mm | 71% | 2.4 m/s | 3.4 |
| 1989 | 21.4°C | 15.4°C | 9.5°C | 28.1°C | 4.9°C | 88 mm | 68% | 2.8 m/s | 3.3 |
| 1988 | 20.4°C | 15.3°C | 10.3°C | 25.4°C | 6.7°C | 74 mm | 76% | 3.2 m/s | 3 |
| 1987 ❄️ | 19.3°C | 13.1°C | 6.9°C | 25.0°C | 3.6°C | 56 mm | 70% | 2.5 m/s | 3.3 |
| 1986 | 20.5°C | 14.6°C | 8.7°C | 26.4°C | 4.9°C | 75 mm | 70% | 2.9 m/s | 3.2 |
| 1985 | 21.7°C | 14.9°C | 8.1°C | 27.9°C | 3.6°C | 26 mm | 54% | 2.9 m/s | 3.6 |
| 1984 | 19.4°C | 14.6°C | 9.8°C | 23.3°C | 6.4°C | 118 mm | 78% | 3.2 m/s | 3.1 |
| 1983 | 23.1°C | 16.1°C | 9.2°C | 30.1°C | 5.0°C | 15 mm | 63% | 2.7 m/s | — |
| 1982 | 20.6°C | 14.7°C | 8.8°C | 27.3°C | 4.0°C | 38 mm | 71% | 2.5 m/s | — |
| 1981 | 21.0°C | 15.0°C | 9.1°C | 28.7°C | 3.5°C | 116 mm | 60% | 3.6 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 21.4°C with lows near 9.2°C (mean 15.3°C), based on 45 years of NASA POWER data.
May averages 54 mm of rainfall in Northam, a relatively wet time of year. The wettest on record was 125 mm in 1999.
The hottest May reached 32.9°C in 2002. The coldest dipped to 2.3°C in 2019.
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 21.2°C to 22.6°C and overnight lows from 9°C to 10°C over the same span.
May is one of the cooler months of the year in Northam and a relatively wet time of year, so plan for around 21.4°C daytime highs and 9.2°C at night.
Not quite — May is the 5th coolest month in Northam, averaging 15.3°C.
For May in Northam, pack light layers you can adjust through the day, with typical highs of 21.4°C and lows of 9.2°C. Bring an umbrella or light rain jacket too.
Relative humidity in May averages 67% — moderately humid.
Average wind speed in May is 2.8 m/s. The windiest May on record averaged 3.6 m/s (1981).
The wettest May on record was 1999 with 125 mm. On average, May sees 54 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 Northam 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.
