Onslow has a warm subtropical climate with warm summers and mild winters.
Temperatures peak in March and drop to their lowest in July, while rainfall is highest during winter months.
Humidity remains moderate throughout the year, especially during winter months, creating warm and dry conditions.
| Month | 🌤️ | Avg High | Avg Temp | Avg Low | Record High | Record Low | Humid % | Rain (mm) | Wind (m/s) | Solar (kWh/m²) |
|---|---|---|---|---|---|---|---|---|---|---|
| January | 🔥 | 31.8°C | 29.1°C | 26.3°C | 41.0°C | 21.5°C | 67% | 38 | 5.0 | 7.65 |
| February | 🔥 | 32.1°C | 29.6°C | 27.2°C | 39.5°C | 22.2°C | 69% | 63 | 4.6 | 7.02 |
| March | 🔥 | 32.3°C | 29.7°C | 27.0°C | 39.5°C | 21.7°C | 65% | 47 | 4.3 | 6.33 |
| April | 🔥 | 30.9°C | 28.2°C | 25.5°C | 37.0°C | 18.9°C | 62% | 20 | 3.9 | 5.29 |
| May | 🌞 | 27.8°C | 25.0°C | 22.2°C | 33.7°C | 16.9°C | 60% | 42 | 3.9 | 4.38 |
| June | 🌞 | 25.0°C | 22.3°C | 19.5°C | 29.7°C | 13.4°C | 61% | 40 | 4.2 | 3.90 |
| July | ☀️ | 24.1°C | 21.0°C | 18.0°C | 27.9°C | 12.6°C | 61% | 17 | 4.3 | 4.34 |
| August | ☀️ | 24.8°C | 21.4°C | 18.1°C | 30.0°C | 11.3°C | 62% | 5 | 4.3 | 5.31 |
| September | 🌞 | 26.2°C | 22.6°C | 19.0°C | 32.4°C | 14.7°C | 62% | 2 | 4.8 | 6.44 |
| October | 🌞 | 28.2°C | 24.6°C | 21.0°C | 38.1°C | 15.0°C | 60% | 1 | 5.2 | 7.42 |
| November | 🌞 | 29.2°C | 25.9°C | 22.5°C | 37.2°C | 17.0°C | 62% | 2 | 5.4 | 8.00 |
| December | 🌞 | 30.7°C | 27.6°C | 24.5°C | 38.9°C | 19.7°C | 64% | 8 | 5.3 | 8.06 |
Showing average climate conditions across 45 years (1981–2025)
🧥 Light layers are sufficient — this Mild Winter stays cool without prolonged hard freezes.
🌤️ Early mornings and evenings are most comfortable during this Hot Summer season.
☔ Rainfall is spread across the year with no sharply defined wet season.
Monthly averages · 1981–2025 climate normals · °C
Temperatures rise steadily from spring, peak in March, and gradually decline through autumn into winter.
These seasonal patterns offer comfortable conditions year-round, with warm summers and mild winters.
Monthly rainfall · 1981–2025 seasonal trends · mm/month
Rainfall is concentrated in the winter months. Humidity stays moderate (around 63%), peaking during winter months, which creates warm and dry conditions.
☔ Rainfall is spread across the year with no sharply defined wet season.
Monthly averages · 1981–2025
Across 45 years of records, Onslow's temperature has remained relatively stable over the past decade. Its hottest day reached 41.0°C in January 2022, and its coldest dropped to 11.3°C in August 1986. 2025 was the warmest year overall and 1992 the coolest.
The warmest year in Onslow's recorded history was 2025 (avg: 26.5°C), while the coldest was 1992 (avg: 24.7°C).
Average annual high/low · Last 30 years · °C
Total annual precipitation · Last 30 years · mm/year
| Year | Avg High | Avg Temp | Avg Low | Hottest Day | Coldest Day | Rainfall (mm) | Avg Humidity | Avg Wind |
|---|---|---|---|---|---|---|---|---|
2025 🔥 | 29.4°C | 26.5°C | 23.6°C | 38.8°C | 13.4°C | 259 | 61% | 4.5 m/s |
2024 | 29.3°C | 26.4°C | 23.6°C | 37.7°C | 14.3°C | 167 | 63% | 4.4 m/s |
2023 | 28.9°C | 25.8°C | 22.7°C | 38.9°C | 13.6°C | 135 | 61% | 4.5 m/s |
2022 | 28.2°C | 25.4°C | 22.5°C | 41.0°C | 13.8°C | 399 | 64% | 4.6 m/s |
2021 | 28.6°C | 25.6°C | 22.7°C | 39.0°C | 13.4°C | 260 | 62% | 4.6 m/s |
2020 | 29.1°C | 26.1°C | 23.1°C | 36.5°C | 15.6°C | 194 | 61% | 4.5 m/s |
2019 | 29.4°C | 26.2°C | 22.9°C | 38.5°C | 14.9°C | 146 | 61% | 4.5 m/s |
2018 | 28.5°C | 25.4°C | 22.3°C | 37.8°C | 14.2°C | 106 | 62% | 4.8 m/s |
2017 | 28.6°C | 25.6°C | 22.6°C | 37.1°C | 14.2°C | 208 | 62% | 4.6 m/s |
2016 | 28.3°C | 25.4°C | 22.4°C | 38.6°C | 14.3°C | 267 | 64% | 4.7 m/s |
Showing 1 to 10 of 45 years
Based on 45 years of data (1981–2025), March is typically the hottest month in Onslow, Western Australia, with average high temperatures around 32.3°C.
July is the coldest month in Onslow, with average low temperatures around 18.0°C.
February receives the most rainfall with approximately 63 mm, while October is the driest with 1 mm.
The highest recorded temperature was 41.0°C in January 2022. This is part of the historical record spanning 1981–2025.
The lowest recorded temperature was 11.3°C in August 1986.
This page covers 45 years of climate data from 1981 to 2025. As new data is added to the database the page automatically reflects the updated coverage.
Onslow receives the most sunlight in December with an average solar radiation of 8.06 kWh/m²/day. This solar radiation data, sourced from NASA POWER, is useful for solar energy planning and agriculture in Western Australia.
All climate data is sourced from NASA POWER (Prediction Of Worldwide Energy Resources), based on MERRA-2 satellite and model data. It provides monthly averages for temperature, precipitation, humidity, wind speed, and solar radiation.
All weather data is sourced from NASA POWER (Prediction of Worldwide Energy Resources), a NASA project providing solar and meteorological data for renewable energy, building efficiency, and agricultural research.
