Have you noticed UK sunsets (and sunrises) have been looking especially vivid this week?
Well, it’s not just you. There’s a reason for it – but it’s not one that’s going to fill you with joy.
It all stems from the smoke which is blowing across from the wildfires in North America and filled up UK skies.
Canada has struggled with hundreds of blazes across June, exacerbated by the heat.
While the country often has wildfires, this year they seem to be particularly potent.
This already had a knock-on effect for New York and other cities on the US’s northeast coast earlier this month, when the skies there turned an ominous, hazy orange for several days, which social media dubbed apocalyptic.
But now it’s arrived in the UK after strong atmospheric winds have pushed it across the Atlantic Ocean.
The Met Office caught the smoke’s movement in a series of alarming satellite images, as you can see below.
So, the sunsets are extra beautiful because all the colours which make up the sunlight refract differently.
Reds and oranges have longer wavelengths, meaning these colours are enhanced by the smoke, while blues and violets have shorter wavelengths, so they’re not as visible and get cut off by the particles.
US-based meteorologist Daphne Thompson explained to CPR News that smoke puts extra particles into the atmosphere, meaning the red light is “scattering over even more of those particles” – which explains the very red sunsets and sunrises people have seen in the UK.
Meanwhile, those in the US and Canada have been urged to limit outdoor activities where they can if they live in areas particularly affected by the smoke.
More than a million Americans have also been encouraged to wear a mask outside, as authorities issue air quality alerts until midnight tonight, from Wisconsin and northern Illinois to Michigan, New York and the East Coast.
The smoke can be dangerous because it can cause shortness of breath and irritated eyes, as well as worsen asthma and heart disease, in severe cases.