Climate Insights for Casterton

The climate in Casterton is temperate. The average annual temperature is 14°C and approximately 551mm of precipitation falls per year. July is the wettest month, receiving around 64mm of rainfall. Casterton is in the Southern Hemisphere. The seasons are reversed — summer runs from December to February, while winter falls between June and August. The summer months are: January, February, December. The coldest months are July, June, August, when temperatures can drop to 6°C.

Temperatures in Casterton vary considerably across the year, with a 21°C difference between the coldest and warmest months. The warmest month is January, when average highs reach 27°C and the mean temperature sits around 20°C. July is the coolest month, with minimum temperatures around 6°C and an average of 8°C. On average, daily temperatures fluctuate by about 10°C between overnight lows and afternoon highs. The sharpest temperature change occurs between March and April, with a 3°C shift in average temperatures.

Casterton is a relatively dry area, receiving approximately 551mm of precipitation annually, which averages out to around 46mm per month. The wettest month is July, averaging 64mm of rainfall. September and August also tend to see above-average precipitation. The driest month is February, with just 15mm. That's 49mm less than July, the wettest month. Precipitation varies noticeably between seasons, with the second half (July to December) of the year generally seeing more rainfall.

Casterton is mildly breezy, with an average annual wind speed of 20km/h. For context, sustained winds below 12km/h are generally light, while anything above 25km/h is considered strong. The windiest month is August, averaging 21km/h, noticeable enough to affect lighter outdoor activities. The calmest conditions occur in April, with average winds dropping to 18km/h, making it an ideal period for wind-sensitive activities. Wind conditions are fairly consistent throughout the year, varying by only 3km/h between the calmest and windiest months.

It is currently autumn in Casterton, which began on March 20, 2026. Casterton is in the Southern Hemisphere, where the seasons are reversed — spring starts in September, summer in December, autumn in March, and winter in June. The warmest period peaks in January at around 27°C, while the coldest stretch bottoms out in July near 6°C. Winter is next, beginning on June 21, 2026 — 89 days from now.

The best time to visit Casterton is during January, February, March, November and December, when the weather is most comfortable for travellers. During these months, average temperatures hover around 18°C with modest rainfall averaging 33mm per month. By contrast, July can be quite cold with temperatures dropping to 6°C. A light rain jacket is recommended, though showers are generally brief and shouldn't disrupt your plans.

The table below shows monthly climate averages for Casterton based on historical weather data. Min and max temperatures represent typical overnight lows and afternoon highs for each month, shown in degrees Celsius (°C). Precipitation is measured in millimetres (mm) and indicates the average total rainfall per month. Wind speed is the average sustained speed in kilometres per hour (km/h). All values are based on averages from over 10 years of historical weather data. The current month is highlighted for quick reference.