Heatwave

 

Heat waves are a deadly meteorological extreme, killing many more people each year than tropical cyclones, bushfires, thunderstorms and floods. There is no universally accepted definition of a “heatwave” however a simple and easy to remember definition is the 5/5 rule – that is five days in a row where the maximum temperature is five or more degrees Celsius above average.

This rule is important to consider as average temperature varies considerably between towns around Australia. For example, the long term average maximum temperature at Darwin Airport during November is 33.3 degrees Celsius while the average maximum temperature at Melbourne in November is 21.9 degrees Celsius. So, 5 consecutive days where the maximum temperature is around 30 degrees Celsius would constitute a heat wave for Melbourne in November but not for Darwin.