Call this a heatwave that would justify blackouts? Hardly feels like it

Swimmers enjoy Bondi Beach on Wednesday in preparation for a warm Sydney day. Picture: Getty Images

You call this a heatwave?

A forecast for Sydney’s CBD of 34C and an actual recorded top of 33C? The first day the mercury had hit 30C in almost three weeks? Hardly feels like it.

Over the past 10 summers, Sydney recorded at least one run of three days or more above 30C. In three of those summers, the run extended to five days, and on occasion, there was a top temperature of 40C or higher.

Across those 10 years, Sydney had six days when the temperature passed 40C.

And while Wednesday’s hot weather came three days before the official start of summer, a 30C-plus day in November is nothing out of the ordinary for Sydney. In 2015, the monitoring station at Observatory Hill recorded three in a row from November 18–20.

Of course, Sydney’s CBD temperatures are generally below those recorded in the western suburbs – as they were on Wednesday – but nowhere in NSW was in “scorcher” territory. Not one location hit 40C – Penrith narrowly missed the mark – and residents of a renowned hot spot such as Dubbo wouldn’t have raised an eyebrow at reaching 31C at this time of year.

Anyway, the quantum of the top temperature in any one location is not the critical point here. It’s the rhetoric and messaging that Wednesday’s conditions were out of the ordinary, part of a prolonged hot spell and a mitigating factor for the problems that have beset the energy network.

The Bureau of Meteorology’s definition of a heatwave is “when the maximum and minimum temperatures are unusually hot over three days”. It does not quantify “unusually”.

The bureau this week issued a heatwave warning for NSW covering Tuesday to Friday and applying to metropolitan Sydney, the mid-north coast, the Hunter, the Illawarra, the south coast and the southern tablelands. The last of these was withdrawn on Wednesday.

Users of the bureau’s popular app in NSW couldn’t have missed the warning. If they didn’t get a notification, the bright yellow box at the top of the screen was hard to miss.

Yes, it was very warm in Sydney and even hotter in the outer suburbs where it reached as high as 39.9C. But compared with heatwaves of the past – which haven’t troubled the energy network – this wasn’t what you would call a red-flag weather crisis.

And if we can’t use our dishwashers and washing machines with the thermometer at 32.9C, imagine what happens when we have another January 18, 2013 – the day Sydney hit its record maximum temperature of 45.8C. Now that is enough to get you hot under the collar.