We were expecting a hotter El Niño summer this year, but many Australians have been caught off-guard by the humidity creating muggy conditions in several states.

And it comes at a time when the cost-of-living is biting hard. 

It may seem like the only solution is to crank up the air conditioner, but many people don’t have one. 

And for those who do, many are worried about how expensive they can be to run. 

Plus, there’s also the environmental impact of burning through all that electricity. 

So here are few low-cost, lower energy ways to keep cool during high humidity.

But before we get into that, let’s quickly unpack why high humidity is so unpleasant. 

What is humidity?

It’s the amount of water vapour molecules in the air. 

It’s tracked by a measure officially called relative humidity (RH), which is written as a percentage — going up to 100 per cent. 

But we typically just say “the humidity” instead of “relative humidity” — even the Bureau of Meteorology (BOM) just has it as “humidity” on its app.

The closer the humidity reading is to 100, the yuckier you’ll probably feel. 

Why does high humidity feel so gross?

Because, typically, the human body’s response to heat produces sweat. 

And in high humidity, the sweat lingers instead of evaporating — which can make you feel sticky.

Here’s how ABC meteorologist Tom Saunders explains it:

“A human’s natural cooling mechanism is through sweat evaporating off the skin, a process feasible due to an energy transfer during the phase change of sweat from a liquid to a gas.

“But this cooling becomes far less efficient during high humidity as the sweat evaporates at a much slower rate since the air is already saturated with moisture.

“It can therefore feel up to around seven degrees warmer during high humidity, expressed by the apparent temperature (AT) which is based on a mathematical model of an adult, walking outdoors, in the shade.

“The AT is equivalent to the temperature that would bring the same amount of discomfort during normal humidity as that experienced under the current ambient temperature and humidity.”

What can you do to reduce humidity in your home?

We went to Ollie Jay, a professor of heat and health at the University of Sydney.

He’s the director of the Heat and Health Research Incubator, a project geared towards coming up with solutions to help us better cope with heatwaves. 

“It is difficult to make the condition less humid,” Professor Jay says. 

“The best bet is to use interventions that reduce the effect of humidity on the body — this after all is the problem!”

How to keep cool without an air conditioner

Electric fans work really well at cooling us in high humidity — and are much cheaper to run than an air conditioner. 

“Moving air is a very effective way, it’s a clean way, accessible way of keeping cool in heat waves, if it’s below 40 degrees Celsius,” Professor Jay explains in a university podcast.

It’s even more effective if you mist your skin with water while sitting in front of the fan. 

Depending on where you are, you might be able to also dampen your clothes too. 

But it’s crucial to get airflow going — so set up a fan or catch a breeze. 

“Wetting clothing maximises water on the skin surface and therefore evaporative potential,” Professor Jay says. 

“It is true that the humidity will blunt the potential for evaporative heat loss, but if you increase air flow across the skin, a wet surface will rapidly cool you down because the moisture will start to rapidly evaporate.”

But there is a point where, when it gets too hot, fans can actually make you hotter.

In these conditions, he suggests using conductive strategies like:

• An ice pack on your neck
• Ice in a towel around your neck
• Putting your feet in a bucket of cold water
• Having a cold bath or shower

State government health departments also suggest going to public places that have air conditioning — think shopping centres and libraries. 

But this is limited by your ability to get around, depends on how close you live to those places and, because they’re public places, can mean you’re less relaxed than you would at home. 

What settings to put your air conditioner on

Professor Jay says that, obviously, air conditioners are more effective than fans.

“Air conditioning cools people by cooling the air,” he says.

“Fans cool people by moving the air — not cooling it.”

The problem with air conditioners is that, even if you have one, they’re expensive to run and have a bigger environmental impact than a fan. 

So he suggests combining your air conditioner with a fan.

The idea is that, instead of turning the temperature way down — which burns through more power — you set your air conditioner to a moderate temperature and move the air around with a fan. 

“If you move air more in an indoor environment, the temperature at which you [feel like you’re too hot] is hotter,” Professor Jay says. 

“So you feel the same at 23 degrees with still air as you will at 27 degrees with air moving, because we’re cooling the person, instead of cooling the air.”

Heat and Health Research Incubator researchers worked out how much less energy this method would use and were astounded. 

“You will feel just as comfortable but will use 70 per cent less electricity,” Professor Jay says. 

Just make sure you’re feeling the force of the fan. 

“Air flow should be perceptible but is still modest,” he says. 

“The best effect was at an air speed of 0.8 m/s — equivalent to the medium setting on a typical pedestal fan from about one metre away.”

Are we still in El Niño?

Yep. 

Typically, we associate an El Niño with a hot, dry summer, however, there’s been a lot of wet weather around the country lately.

Senior BOM meteorologist Andrea Peace says we’re still very much in an El Nino.

“This is because sea surface temperatures are still meeting the right criteria,” Ms Peace says. 

“El Nino is known to affect the weather in certain ways, but there is no guarantee of those effects, especially when so many other factors are at play.

One of those factors is the presence of what’s called the Southern Annular Mode (SAM) — a wind belt that encircles Antarctica that, when it’s in its positive phase, moves up towards the equator and can mean increased storms and rain in eastern Australia.

“In spring and summer, a strong positive SAM can mean that southern Australia is influenced by the northern half of high pressure systems, and hence there are more easterly winds bringing moist air from the Tasman Sea,” a BOM fact sheet says. 

“This increased moisture can turn to rain as the winds hit the coast and the Great Dividing Range.”

It’s unusual for this to be happening for such a long time during an El Nino, Ms Peace says. 

“That’s actually more typical during La Nina.”