Brisbane, along with other parts of southeast Queensland and northeast NSW, has sweated through its hottest October day in more than a decade after an uncommon hot change blasted through.

While the morning started off pretty typical of a pleasant October day in Brisbane, with a mild minimum of 15 degrees, and a cooling seabreeze keeping the city below 30 degrees in the morning, conditions changed quickly as a hot change rolled through.

From about 1:20pm, a trough bringing gusty southwesterly winds started to push back against the cooling seabreeze, causing a 5.4°C increase in temperature in one hour, up to a maximum of 36.6°C. This makes it Brisbane's hottest October day in 17 years and its hottest day since December 2019.

Brisbane was not alone in this feat, with Archerfield (36.5°C), Sunshine Coast (33.9°C) in Queensland and Coffs Harbour (35.0°C), Ballina (34.4°C) and Yamba (33.1°C) in NSW all having their hottest days in over 18 months and their hottest October days in at least 8 years.

Image: Westerly winds, and temperatures showing a change sweeping over the region

Not only was the change much warmer than the seabreeze, it was also much drier. Humidity quickly fell from a comfortable 55% near midday to around 16% after the change.

In complete opposition to this warm weather, the same westerly change has made Melbourne feel about 12 degrees for most of today, with frequent cold and gusty showers. The major reason for this difference is the winds had to cross much of inland NSW to reach Brisbane, which typically warms up the airmass outside of winter. 

The westerly winds will continue over the eastern states on Tuesday, although will be a little cooler in the north as the hottest air moves out to sea.