Adelaide just had one of its driest February-to-April periods on record as stubborn high pressure continues to shield southern Australia from autumn rainfall.

The official weather station in Adelaide (West Terrace / ngayirdapira) only received 12 mm of rain in April. Coming off the back of an even drier March (3 mm) and a completely rainless February, the city only registered 15 mm of rain during the last three months.

This was Adelaide’s driest February-to-April period since 1923 and its fourth driest such period since records commenced in 1839. The driest was 3.1 mm in 1923.

Abnormally high mean sea level pressure to the south of Australia has prevented rain-bearing cold fronts from reaching SA so far this autumn. At a time of year when an average of around 88 mm should be falling in Adelaide, the city only received 17% of this amount in the last three months.

Image: Monthly mean sea level pressure anomaly during March 2024, showing an area of pressure to the south of Australia that was about 4 hPa above average for this time of year.

Unfortunately for Adelaide, the pattern of stubborn high pressure to the south of Australia will stick around into the first half of May. This will limit the city’s chances of receiving any substantial rainfall over the next couple of weeks.

According to SA Water, the state’s reservoirs were sitting at 47 % of capacity at the end of April 2024. This was down from 59 % full at the same time last year.