Parts of Australia may see heatwaves before the spring equinox

11 September 2023

The ten-day weather forecast for some parts of NSW are currently predicting several days with maximum temperatures in the vicinity of thirty degrees centigrade. This, at the moment, for Saturday and Sunday, 16 and 17 September, and Tuesday 19 September. These temperature ranges come close to the official definition of a heatwave:

A heatwave occurs when the maximum and the minimum temperatures are unusually hot over a three-day period in a specific location. This is considered in relation to the local climate and past weather at that place.

Such a forecast may not be entirely surprising if not for the fact Australia is only into the first few weeks of spring. Technically though, were the spring equinox — which falls on Saturday 23 September this year — to be observed as the beginning of spring (as is the case in parts of the world), then it would still be winter in Australia. A heatwave in winter, fancy that.

Long range forecasts are not always accurate though, and conditions may change between now and the weekend. Still, such warm temperatures in the middle of September are alarming to say the least.

And for anyone wondering, each season in Australia commence on the first days of March, June, September, and December, because Australia adheres to the meteorological seasonal system. Many northern hemisphere nations however observe the astronomical season convention, meaning seasons change on about the beginning of the third week in March, June, September, and December.