Warning on electric fans over '35°C rule' many people don't realise

Experts are urging everyone to be aware of the ‘35°C’ fan rule as temperatures soar in the UK this week.

Rare red weather warnings have been issued by the Met Office this week over the extreme temperatures that are set to hit.

With record-breaking June highs expected, forecasters have predicted that the heatwave could hit temperatures as hot as 38°C to 40°C in some parts of England and Wales, smashing the June record set in 1976 by several degrees.

This means that many Brits will be rushing to the shops to splash out on fans and paddling pools in an effort to keep warm.

However, with temperatures surpassing 35°C, most people won’t be aware that their trusty electric fan might not be doing the job they want it to - it could instead be making things worse.

Parts of the UK are set to reach between 38°C and 40°C this week (Getty Stock Image)

A warning over using electric fans at 35°C and over

The government has warned that while mechanical fans can be used to increase air movement if temperatures are below 35°C, at temperatures above this number, they may not prevent heat-related illness and could even worsen dehydration.

This is because our skin typically sits at around 35 °C, so when the air around us becomes hotter than this, a fan can blow the hot air directly onto the body, causing us to absorb heat rather than lose it.

Absorbing the heat can mean there’s an increased strain on the heart and speed up dehydration rather than keep us cool.

Because this rule is little-known and most of us would assume a fan is our best bet, councils have sent warnings out to residents.

As reported by The Express, Haringey Council said: "Use electric fans if the air temperature is below 35°C, but do not aim the fan directly at your body, as this can lead to dehydration.”

Using an electric fan if the temperature is above 35°C can worsen dehydration (Getty Stock Image)

The Met Office's red warning

A red warning from the Met Office is reserved for the most severe events, meaning this UK heatwave is set to bring ‘severe and significant impacts,’ including widespread health risks for many, not just those who are normally more vulnerable to the heat, and even danger to life.

Dr Will Lang, chief meteorologist at the Met Office, said: “We are forecasting extreme temperatures in the next few days, particularly on Wednesday and Thursday, when it looks like we’ll be seeing maximum temperatures into the high 30s.

“But also we are stressing very high overnight temperatures, which will be very uncomfortable for vulnerable groups, and very humid conditions as well.”

For advice on how to stay safe in the hot weather, you can visit the Government’s website.