Brisbane just dropped below 20°C for the first time this year, ending a record-breaking run of warm minimum temperatures that obliterated the previous record by more than two weeks.

Prior to this morning, the temperature in Brisbane had not dipped below 20°C since the start of 2024. This 74-day run of minimum temperatures above 20°C was unprecedented for the city, beating the previous record of 59 days from 1978.

Friday morning’s minimum temperature only just spoiled Brisbane’s record-breaking run, dipping to 19.8°C shortly after 5:30am. While not overly cool by Brisbane’s standards, this was the city’s lowest temperature since Christmas morning.

One of the main drivers behind Brisbane’s prolonged spell of warm nights in the opening months of 2024 was abnormally warm water lingering to the east of Australia.

Sea surface temperatures off the east of Qld and NSW have been running around 1 to 3°C above average over the last few months. These warm waters have limited the cooling influence of onshore winds and southerly changes in southeast Qld, resulting in muggy days and warm nights. Brisbane’s monthly minimum temperatures have been running about 1 to 1.5°C warmer than usual since the start of summer.

The unusually humid weather has also been felt across large areas of eastern Australia in recent months, with dew point temperatures running several degrees above average in parts of Qld and NSW over summer. The dew point refers to the temperature the air needs to cool to for condensation to occur. The higher the dew point, the harder it gets for our bodies to lose heat through the evaporation of sweat.

Image: Dew point temperature anomalies during summer 2023-24. Source: ClimateReanlayzer.org

Despite this morning’s low of 19.8°C, Brisbane might struggle to drop back below 20°C for most of the coming week. Days will also be warm, but nothing abnormal for early-autumn, reaching the high-20s to low-30s for at least the next seven days.