This morning, Adelaide Airport experienced its coldest temperature of the year so far, with the mercury falling to 2.4°C. Temperatures were also quite cold in the heart of the city with West Terrace dropping to 4.0°C, the coldest June temperature recorded at that location in about 2 years (coldest since 30 June 2024).

Why was it so cold in Adelaide this morning? Skies were clear and winds were calm during most of the overnight hours, and these conditions enhanced radiational cooling. This weekend also marks the winter solstice, and the long night allowed for an extended period of cooling. It is no coincidence that both locations recorded their minimum temperatures after 7am, or within 30 minutes of sunrise.

Image: Forecast minimum temperatures for 21 June 2026 according to the ECMWF model. Source: Weatherzone. 

The clear skies and light winds that were observed across southern SA early this morning were caused by a ridge of high pressure which was centred just south of the Eyre Peninsula. Similar conditions were observed in Streak Bay, where the temperature fell to 1.9°C this morning, which is the coldest June temperature at that location in 11 years.