May is one of the cooler months of the year in Merredin, with average highs near 21.2°C and lows around 8.9°C (mean 15.1°C). It is a relatively wet time of year, averaging 39 mm of rainfall and 64% relative humidity across the period.
May is one of the cooler months of the year in Merredin. Across 45 years of records, the warmest May in Merredin was 2024 — when the month averaged 17.7°C — while the coldest was 2016 at 13°C. Typical May days reach 21.2°C with nights near 8.9°C. The long-term trend is warming, about 0.2°C per decade.
May is a relatively wet time of year in Merredin, averaging 39 mm of rainfall. The wettest May on record was 1999 with 108 mm, while the driest was 2019 at 7 mm.
Relative humidity in Merredin during May averages 64%. The most humid May was 2014 at 76%, and the least humid was 1985 at 50%.
May receives about 3.5 kWh/m²/day of solar energy in Merredin. The sunniest May was 2000 at 3.9 kWh/m²/day, and the cloudiest was 1999 at 2.9.
Average wind speed in Merredin during May is 3.1 m/s. The windiest May was 1981 at 3.9 m/s, while the calmest was 2008 at 2.3 m/s.
Ranked against the other 11 months using 1981–2025 averages.
| Metric | 1980s | 1990s | 2000s | 2010s | 2020s | Change |
|---|---|---|---|---|---|---|
| Avg Temp | 14.5°C | 15.1°C | 15.3°C | 14.8°C | 15.8°C | +1.3°C |
| Avg High | 20.6°C | 21.0°C | 21.5°C | 21.0°C | 22.2°C | +1.6°C |
| Avg Low | 8.5°C | 9.3°C | 9.0°C | 8.5°C | 9.5°C | +1°C |
| Avg Rain | 51 mm | 42 mm | 33 mm | 28 mm | 44 mm | -7 mm |
May temperatures in Merredin have risen by about 1.4°C between 1981–1985 and 2021–2025.
May has ranged from a record low of 2.2°C (2006) to a record high of 32.8°C (2002).
Rainfall in May is a relatively wet time of year, averaging 39 mm, with a wettest year of 108 mm.
A good time to visit Merredin
May is a good time to visit Merredin, with days averaging 21.2°C and nights around 8.9°C (mean 15.1°C, cooler than Merredin'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 | 23.4°C | 16.6°C | 9.7°C | 30.4°C | 3.1°C | 24 mm | 58% | 3.1 m/s | 3.8 |
| 2024 🔥 | 23.9°C | 17.7°C | 11.5°C | 28.2°C | 6.2°C | 28 mm | 54% | 3 m/s | 3.5 |
| 2023 | 22.1°C | 15.3°C | 8.5°C | 27.3°C | 3.4°C | 21 mm | 56% | 3 m/s | 3.6 |
| 2022 | 21.3°C | 15.2°C | 9.1°C | 28.2°C | 4.1°C | 56 mm | 64% | 3 m/s | 3.5 |
| 2021 | 21.3°C | 15.5°C | 9.8°C | 26.8°C | 3.4°C | 70 mm | 66% | 3 m/s | 3.3 |
| 2020 | 20.9°C | 14.5°C | 8.1°C | 27.5°C | 3.8°C | 67 mm | 61% | 3.6 m/s | 3.6 |
| 2019 | 21.2°C | 14.1°C | 7.1°C | 28.2°C | 2.2°C | 7 mm | 57% | 2.8 m/s | 3.8 |
| 2018 | 22.7°C | 15.8°C | 8.9°C | 29.2°C | 4.6°C | 18 mm | 51% | 3.5 m/s | 3.8 |
| 2017 | 21.2°C | 15.2°C | 9.1°C | 28.9°C | 4.0°C | 19 mm | 66% | 3 m/s | 3.5 |
| 2016 ❄️ | 19.0°C | 13.0°C | 7.0°C | 25.9°C | 3.3°C | 37 mm | 73% | 2.5 m/s | 3.5 |
| 2015 | 20.0°C | 13.8°C | 7.7°C | 24.4°C | 4.2°C | 17 mm | 64% | 3.1 m/s | 3.8 |
| 2014 | 19.9°C | 14.9°C | 9.8°C | 23.2°C | 4.5°C | 52 mm | 76% | 2.7 m/s | 3.2 |
| 2013 | 20.5°C | 14.9°C | 9.2°C | 28.6°C | 4.6°C | 41 mm | 68% | 2.9 m/s | 3.4 |
| 2012 | 22.2°C | 15.7°C | 9.2°C | 27.6°C | 3.9°C | 18 mm | 62% | 2.8 m/s | 3.6 |
| 2011 | 21.4°C | 15.4°C | 9.5°C | 26.0°C | 6.3°C | 38 mm | 63% | 3 m/s | 3.5 |
| 2010 | 21.5°C | 14.7°C | 7.9°C | 28.8°C | 3.5°C | 35 mm | 60% | 3 m/s | 3.6 |
| 2009 | 21.9°C | 15.3°C | 8.8°C | 25.7°C | 3.6°C | 23 mm | 55% | 3.2 m/s | 3.8 |
| 2008 | 22.4°C | 16.1°C | 9.8°C | 27.9°C | 5.3°C | 21 mm | 66% | 2.3 m/s | 3.6 |
| 2007 | 20.1°C | 13.9°C | 7.7°C | 26.6°C | 3.5°C | 20 mm | 67% | 2.7 m/s | 3.6 |
| 2006 | 21.0°C | 14.5°C | 7.9°C | 25.6°C | 2.2°C | 20 mm | 63% | 2.9 m/s | 3.6 |
| 2005 | 22.7°C | 17.1°C | 11.6°C | 29.2°C | 7.5°C | 71 mm | 69% | 3.3 m/s | 3 |
| 2004 | 19.9°C | 14.0°C | 8.0°C | 28.3°C | 3.5°C | 57 mm | 65% | 3.1 m/s | 3.4 |
| 2003 | 22.2°C | 16.1°C | 9.9°C | 28.4°C | 3.9°C | 62 mm | 62% | 3.5 m/s | 3.4 |
| 2002 | 23.1°C | 16.5°C | 9.9°C | 32.8°C | 5.8°C | 10 mm | 61% | 3 m/s | 3.4 |
| 2001 | 21.6°C | 15.6°C | 9.6°C | 29.5°C | 5.2°C | 41 mm | 66% | 2.8 m/s | 3.3 |
| 2000 | 20.0°C | 13.5°C | 7.0°C | 25.3°C | 4.3°C | 8 mm | 64% | 2.7 m/s | 3.9 |
| 1999 🌧️ | 21.1°C | 15.7°C | 10.4°C | 28.7°C | 3.3°C | 108 mm | 73% | 3.1 m/s | 2.9 |
| 1998 | 23.0°C | 17.1°C | 11.1°C | 30.0°C | 5.5°C | 30 mm | 67% | 3.1 m/s | 3.1 |
| 1997 | 19.7°C | 14.5°C | 9.3°C | 26.9°C | 3.8°C | 32 mm | 71% | 3.6 m/s | 3 |
| 1996 | 22.4°C | 15.9°C | 9.4°C | 28.8°C | 5.1°C | 22 mm | 56% | 3.2 m/s | 3.5 |
| 1995 | 19.4°C | 13.4°C | 7.5°C | 24.2°C | 3.4°C | 51 mm | 68% | 3.4 m/s | 3.6 |
| 1994 | 22.5°C | 16.2°C | 9.8°C | 28.6°C | 6.2°C | 51 mm | 60% | 3.2 m/s | 3.6 |
| 1993 | 19.8°C | 13.9°C | 8.1°C | 24.6°C | 3.1°C | 65 mm | 67% | 3 m/s | 3.4 |
| 1992 | 19.4°C | 13.9°C | 8.5°C | 23.2°C | 4.2°C | 10 mm | 72% | 3 m/s | 3.6 |
| 1991 | 21.6°C | 15.7°C | 9.7°C | 28.8°C | 4.8°C | 35 mm | 61% | 3.4 m/s | 3.4 |
| 1990 | 21.0°C | 15.0°C | 9.1°C | 30.1°C | 4.2°C | 14 mm | 67% | 2.7 m/s | 3.4 |
| 1989 | 20.6°C | 14.8°C | 8.9°C | 26.3°C | 4.3°C | 80 mm | 67% | 3.1 m/s | 3.3 |
| 1988 | 20.2°C | 15.0°C | 9.7°C | 25.7°C | 6.2°C | 59 mm | 74% | 3.5 m/s | 3.1 |
| 1987 | 19.4°C | 13.1°C | 6.7°C | 25.6°C | 4.0°C | 38 mm | 65% | 2.9 m/s | 3.4 |
| 1986 | 20.5°C | 14.4°C | 8.3°C | 25.2°C | 4.9°C | 54 mm | 66% | 3.2 m/s | 3.4 |
| 1985 | 21.5°C | 14.7°C | 7.9°C | 29.7°C | 3.3°C | 14 mm | 50% | 3.2 m/s | 3.7 |
| 1984 | 19.2°C | 14.0°C | 8.8°C | 22.6°C | 4.5°C | 101 mm | 75% | 3.5 m/s | 3.3 |
| 1983 | 23.0°C | 15.9°C | 8.9°C | 31.0°C | 4.7°C | 8 mm | 55% | 3 m/s | — |
| 1982 | 20.3°C | 14.4°C | 8.6°C | 26.5°C | 3.8°C | 30 mm | 67% | 2.7 m/s | — |
| 1981 | 20.5°C | 14.6°C | 8.7°C | 28.8°C | 4.4°C | 76 mm | 59% | 3.9 m/s | — |
Actual recorded May data for each year, 1981–2025 — sourced from NASA POWER.
The average high in May is around 21.2°C with lows near 8.9°C (mean 15.1°C), based on 45 years of NASA POWER data.
May averages 39 mm of rainfall in Merredin, a relatively wet time of year. The wettest on record was 108 mm in 1999.
The hottest May reached 32.8°C in 2002. The coldest dipped to 2.2°C in 2006.
Comparing the earliest years on record (1981–1985) with the most recent (2021–2025), average May temperatures have risen by about 1.4°C. Daytime highs moved from 20.9°C to 22.4°C and overnight lows from 8.6°C to 9.7°C over the same span.
May is one of the cooler months of the year in Merredin and a relatively wet time of year, so plan for around 21.2°C daytime highs and 8.9°C at night.
Not quite — May is the 5th coolest month in Merredin, averaging 15.1°C.
For May in Merredin, pack light layers you can adjust through the day, with typical highs of 21.2°C and lows of 8.9°C.
Relative humidity in May averages 64% — moderately humid.
Average wind speed in May is 3.1 m/s. The windiest May on record averaged 3.9 m/s (1981).
The wettest May on record was 1999 with 108 mm. On average, May sees 39 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 Merredin 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.
