May is one of the cooler months of the year in Perth, with average highs near 21.1°C and lows around 16.1°C (mean 18.6°C). It is a relatively wet time of year, averaging 89 mm of rainfall and 69% relative humidity across the period.
May is one of the cooler months of the year in Perth. Across 45 years of records, the warmest May in Perth was 2024 — when the month averaged 20.5°C — while the coldest was 1987 at 17.2°C. Typical May days reach 21.1°C with nights near 16.1°C. The long-term May temperature trend is broadly flat.
May is a relatively wet time of year in Perth, averaging 89 mm of rainfall. The wettest May on record was 1981 with 196 mm, while the driest was 2019 at 13 mm.
Relative humidity in Perth during May averages 69%. The most humid May was 2005 at 76%, and the least humid was 1985 at 63%.
May receives about 3.3 kWh/m²/day of solar energy in Perth. The sunniest May was 2019 at 3.7 kWh/m²/day, and the cloudiest was 1999 at 2.8.
Average wind speed in Perth during May is 4.9 m/s. The windiest May was 1981 at 6 m/s, while the calmest was 2008 at 4 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 18.4°C | 18.7°C | 18.7°C | 18.3°C | 19.1°C | +0.7°C |
| Avg High | 20.7°C | 21.1°C | 21.2°C | 20.9°C | 21.7°C | +1°C |
| Avg Low | 16.1°C | 16.4°C | 16.2°C | 15.8°C | 16.3°C | +0.2°C |
| Avg Rain | 113 mm | 101 mm | 92 mm | 73 mm | 55 mm | -57 mm |
May temperatures in Perth have risen by about 0.6°C between 1981–1985 and 2021–2025.
May has ranged from a record low of 11.3°C (2006) to a record high of 28°C (2003).
Rainfall in May is a relatively wet time of year, averaging 89 mm, with a wettest year of 196 mm.
Daytime highs and overnight lows have shifted differently — highs rose about 0.2°C per decade while lows rose 0°C per decade, widening the gap between day and night.
A good time to visit Perth
May is a good time to visit Perth, with days averaging 21.1°C and nights around 16.1°C (mean 18.6°C, close to Perth's yearly average) and higher rainfall. December 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 | 22.9°C | 19.8°C | 16.6°C | 27.5°C | 12.5°C | 41 mm | 68% | 4.9 m/s | 3.6 |
| 2024 🔥 | 23.2°C | 20.5°C | 17.7°C | 26.5°C | 15.3°C | 52 mm | 66% | 4.7 m/s | 3.2 |
| 2023 | 21.4°C | 18.4°C | 15.4°C | 24.7°C | 12.6°C | 31 mm | 67% | 5.1 m/s | 3.3 |
| 2022 | 20.9°C | 18.4°C | 16.0°C | 24.3°C | 13.0°C | 70 mm | 70% | 4.8 m/s | 3.4 |
| 2021 | 21.3°C | 19.0°C | 16.6°C | 25.4°C | 13.8°C | 55 mm | 70% | 4.9 m/s | 3.1 |
| 2020 | 20.7°C | 18.2°C | 15.7°C | 24.4°C | 12.8°C | 83 mm | 68% | 5.6 m/s | 3.3 |
| 2019 | 20.7°C | 17.7°C | 14.7°C | 24.1°C | 11.4°C | 13 mm | 66% | 4.5 m/s | 3.7 |
| 2018 | 22.3°C | 19.1°C | 15.9°C | 27.2°C | 13.0°C | 52 mm | 64% | 5.2 m/s | 3.6 |
| 2017 | 21.1°C | 18.7°C | 16.2°C | 25.8°C | 13.7°C | 42 mm | 70% | 4.5 m/s | 3.5 |
| 2016 | 19.5°C | 17.6°C | 15.6°C | 22.6°C | 12.9°C | 75 mm | 71% | 4.4 m/s | 3.3 |
| 2015 | 20.2°C | 17.6°C | 15.0°C | 23.8°C | 12.1°C | 59 mm | 68% | 5 m/s | 3.6 |
| 2014 | 20.3°C | 18.7°C | 17.1°C | 22.8°C | 12.8°C | 119 mm | 74% | 4.8 m/s | 2.9 |
| 2013 | 20.4°C | 18.2°C | 15.9°C | 24.1°C | 11.6°C | 155 mm | 71% | 4.8 m/s | 3.3 |
| 2012 | 21.5°C | 18.8°C | 16.1°C | 25.3°C | 12.5°C | 52 mm | 69% | 4.4 m/s | 3.5 |
| 2011 | 22.2°C | 19.3°C | 16.4°C | 25.8°C | 13.9°C | 82 mm | 67% | 5 m/s | 3.5 |
| 2010 | 20.4°C | 17.8°C | 15.1°C | 26.1°C | 12.1°C | 84 mm | 67% | 4.5 m/s | 3.4 |
| 2009 | 22.4°C | 19.0°C | 15.6°C | 25.6°C | 11.9°C | 54 mm | 65% | 5 m/s | 3.6 |
| 2008 | 21.0°C | 19.1°C | 17.1°C | 24.5°C | 14.4°C | 104 mm | 73% | 4 m/s | 3.2 |
| 2007 | 19.6°C | 17.7°C | 15.8°C | 25.2°C | 12.7°C | 52 mm | 70% | 4.5 m/s | 3.2 |
| 2006 | 21.1°C | 18.0°C | 14.9°C | 26.2°C | 11.3°C | 41 mm | 69% | 5 m/s | 3.4 |
| 2005 | 22.2°C | 19.7°C | 17.2°C | 26.4°C | 13.9°C | 190 mm | 76% | 5.4 m/s | 3 |
| 2004 | 20.3°C | 18.1°C | 15.8°C | 25.4°C | 12.1°C | 122 mm | 68% | 5.3 m/s | 3.2 |
| 2003 | 22.2°C | 19.5°C | 16.8°C | 28.0°C | 13.3°C | 100 mm | 68% | 5.2 m/s | 3.3 |
| 2002 | 21.2°C | 18.9°C | 16.7°C | 27.5°C | 13.4°C | 73 mm | 70% | 4.9 m/s | 3.3 |
| 2001 | 20.6°C | 18.5°C | 16.4°C | 23.6°C | 12.5°C | 127 mm | 72% | 4.6 m/s | 3 |
| 2000 | 21.3°C | 18.6°C | 16.0°C | 24.8°C | 12.7°C | 56 mm | 64% | 4.7 m/s | 3.6 |
| 1999 | 22.0°C | 20.2°C | 18.3°C | 26.1°C | 13.8°C | 131 mm | 70% | 5.2 m/s | 2.8 |
| 1998 | 22.4°C | 19.7°C | 17.0°C | 27.0°C | 13.3°C | 78 mm | 68% | 4.6 m/s | 3.1 |
| 1997 | 20.7°C | 18.5°C | 16.3°C | 25.6°C | 12.8°C | 105 mm | 71% | 5.6 m/s | 3.1 |
| 1996 | 22.2°C | 19.4°C | 16.6°C | 25.9°C | 13.0°C | 56 mm | 64% | 4.9 m/s | 3.3 |
| 1995 | 20.4°C | 17.8°C | 15.3°C | 25.6°C | 12.3°C | 161 mm | 66% | 5.4 m/s | 3.5 |
| 1994 | 21.6°C | 19.3°C | 17.0°C | 27.2°C | 13.9°C | 114 mm | 70% | 5.1 m/s | 3.4 |
| 1993 | 20.4°C | 17.8°C | 15.2°C | 23.6°C | 12.8°C | 103 mm | 70% | 4.7 m/s | 3.2 |
| 1992 | 19.9°C | 17.9°C | 15.9°C | 21.9°C | 12.5°C | 94 mm | 70% | 5.3 m/s | 3.4 |
| 1991 | 20.9°C | 18.7°C | 16.5°C | 25.7°C | 13.7°C | 99 mm | 69% | 5.1 m/s | 3 |
| 1990 | 20.1°C | 17.9°C | 15.6°C | 23.3°C | 11.8°C | 68 mm | 72% | 4.4 m/s | 3.2 |
| 1989 | 21.8°C | 19.1°C | 16.5°C | 26.3°C | 13.5°C | 131 mm | 70% | 5.1 m/s | 3.2 |
| 1988 | 20.7°C | 18.8°C | 16.9°C | 25.3°C | 14.2°C | 140 mm | 72% | 5.7 m/s | 3 |
| 1987 ❄️ | 19.6°C | 17.2°C | 14.7°C | 23.8°C | 12.3°C | 89 mm | 69% | 4.6 m/s | 3 |
| 1986 | 20.0°C | 17.8°C | 15.7°C | 23.5°C | 11.9°C | 145 mm | 71% | 5 m/s | 3.1 |
| 1985 | 21.3°C | 18.2°C | 15.0°C | 25.4°C | 13.0°C | 70 mm | 63% | 4.9 m/s | 3.4 |
| 1984 | 20.4°C | 18.6°C | 16.8°C | 23.1°C | 13.5°C | 159 mm | 71% | 5.7 m/s | 2.9 |
| 1983 | 21.5°C | 19.3°C | 17.0°C | 25.5°C | 14.1°C | 24 mm | 67% | 4.3 m/s | — |
| 1982 | 20.0°C | 18.0°C | 15.9°C | 23.3°C | 12.6°C | 61 mm | 69% | 4.5 m/s | — |
| 1981 🌧️ | 21.3°C | 18.7°C | 16.0°C | 25.6°C | 12.6°C | 196 mm | 66% | 6 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 21.1°C with lows near 16.1°C (mean 18.6°C), based on 45 years of NASA POWER data.
May averages 89 mm of rainfall in Perth, a relatively wet time of year. The wettest on record was 196 mm in 1981.
The hottest May reached 28°C in 2003. The coldest dipped to 11.3°C in 2006.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 0.6°C. Daytime highs moved from 20.9°C to 21.9°C and overnight lows from 16.1°C to 16.5°C over the same span.
May is one of the cooler months of the year in Perth and a relatively wet time of year, so plan for around 21.1°C daytime highs and 16.1°C at night.
Not quite — May is the 6th coolest month in Perth, averaging 18.6°C.
For May in Perth, pack light layers you can adjust through the day, with typical highs of 21.1°C and lows of 16.1°C. Bring an umbrella or light rain jacket too.
Relative humidity in May averages 69% — moderately humid.
Average wind speed in May is 4.9 m/s. The windiest May on record averaged 6 m/s (1981).
The wettest May on record was 1981 with 196 mm. On average, May sees 89 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 Perth 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.
