Weather UK: When is it officially a ‘heatwave’ and why do they happen?
Unless you’ve taken an extended sabbatical at the North Pole recently, you’ve probably noticed that thermometers in London and across the UK seem to have been permanently stuck at ‘Beer Garden.’
In a country famous worldwide for its often-disappointing climate, the good news is the hot weather is set to continue and potentially even reach record-breaking levels by the weekend.
The Met Office has even issued an amber weather warning for extreme heat this weekend.
The weather has long been considered our ‘national conversation’, and whether you’re looking for a new piece of small talk to bring up in the queue for the bank or are just interested in all things meteorological, why not cast your eye over the official definition of a heatwave?
What constitutes a ‘heatwave’?
The official definition for what constitutes a heatwave might not be as simple as you think and can vary around the country.
According to the Met Office: ‘A UK heatwave threshold is met when a location records a period of at least three consecutive days with daily maximum temperatures meeting or exceeding the heatwave temperature threshold. The threshold varies by UK county.’
They can also vary from country to country. In the US, for example, the NOAA (National Oceanic and Atmospheric Administration) simply define a heatwave as ‘a period of unusually hot weather that typically lasts two or more days.’
While many of us may enjoy the increased temperature, the WHO (World Health Organisation) warn that: ‘Heatwaves are among the most dangerous of natural hazards, but rarely receive adequate attention because their death tolls and destruction are not always immediately obvious.’
‘From 1998-2017, more than 166,000 people died due to heatwaves, including more than 70,000 who died during the 2003 heatwave in Europe.’
Why do heatwaves happen?
Heatwaves result from high pressure developing across an area of the country and are, unsurprisingly, more common in the Summer when temperatures generally improve.
The Met Office go on to say: ‘High pressure systems are slow moving and can persist over an area for a prolonged period of time, such as days or weeks. They can occur in the UK due to the location of the jet stream, which is usually to the north of the UK in the Summer. This can allow high pressure to develop over the UK resulting in persistent dry and settled weather.’
Research has shown a link between extreme weather events, like heatwaves, and climate change. The frequency of heatwaves has been linked to the concentration of greenhouse gases, and they could become as frequent as every other year by 2050.
MORE : Homes left without water in 28°C weather after main bursts
MORE : What is the hottest temperature ever recorded in the UK as the heatwave hits?
MORE : All ambulance services in England on critical footing due to heatwave and Covid
Follow Metro across our social channels, on Facebook, Twitter and Instagram
Share your views in the comments below