Seasonal Climate Outlook

Spring outlook from the Bureau of Meteorology

The Bureau of Meteorology indicates for spring, September to November, a higher chance of rainfall being in the lowest 20% (decile 2) of the historical range. However, skill is between 45-65% for the South West Land Division.

Rainfall outlook for spring, September to November, from the Bureau of Meteorology,

Accuracy map for the ACCESS-S2 Bureau of Meteorology model, for the chance of being in the bottom quintile rainfall for September to November for Australia

One of the reasons for the drier than normal rainfall outlook for spring, is the forecast of higher than normal mean sea level pressure over Australia. This will act as a blocking high pressure system, reducing rainfall to the South West Land Division.

Mean sea level pressure forecast for September to November 2023 from the Bureau of Meteorology

Maximum temperature outlook from the Bureau, is indicating it is more than likely that maximum temperatures will be in the highest 20% of the historical range for September to November. Skill of this outlook is 65-100%, based on past accuracy of the ACCESS-S2 model at this time of year for maximum temperature.

Maximum temperature map, chance of being in the highest 20% of the historical range for September to November from the Bureau of Meteorology’s ACCESS-S2 model

Accuracy map of chance of being in the upper quintile maximum temperature for September to November

Frost potential

Due to the outlook of reduced rainfall for spring, the occurrence of frost, temperatures below 2°C, may be higher than normal this spring, due to reduced cloud cover. Based on 1975-2022 September data, locations can get up to 5-6 frost events in September, depending on the location.

Average number of days below 2°C for the South West Land Division in September 1975-2022