It’s the build-up in northern Australia – the time of year when heat and humidity get worse ahead of the wet season. Common phrases such as “going troppo” or “mango madness” give a sense of the effects. Tempers fray and tensions rise.

There’s now emerging evidence that humidity makes heat more dangerous. Humid heatwaves – where high temperatures combine with high humidity – are potentially more dangerous than dry heatwaves.

Elsewhere in the world, humid heatwaves are already claiming lives. Over 1,300 pilgrims died in Saudi Arabia in 2024 due to lethal levels of humidity and heat, while India and Pakistan have also been hard hit.

Our recent research in the Northern Territory found more people came to emergency departments during intense humid heatwaves than comparable dry heatwaves.

The problem is, we’re not warning people about this combined threat. Australia’s heatwave warning systems focus only on temperature – not on humidity.

Intense heat stresses the body. Humidity can make this worse.

The human body relies heavily on sweating to regulate temperature. When sweat evaporates from the skin, it removes heat and helps keep the body cool. When humidity is high, evaporation doesn’t work as well and it’s harder for the body to release heat and........

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