An “unusual” reddish sky and red-looking sun have been reported across many parts of England.
The phenomenon was initially seen in the west of England and Wales before spreading to other areas.
BBC weather presenter Simon King said it was due to the remnants of Hurricane Ophelia dragging in tropical air and dust from the Sahara.
He added that debris from forest fires in Portugal and Spain was also playing a part.
The dust has caused shorter wavelength blue light to be scattered, making it appear red.
He said: “Ophelia originated in the Azores where it was a hurricane and as it tracked its way northwards it dragged in tropical air from the Sahara.”
This meant dust from the Sahara was brought with it, he said.
“The dust gets picked up into the air and goes high up into the atmosphere, and that dust has been dragged high up in the atmosphere above the UK,” Mr King explained.
The particles in the air cause blue light to scatter, leaving longer-wavelength red light to shine through.
The Met Office said the “vast majority” of the dust was as a result of forest fires in Iberia, which have sent debris into the air and that has been dragged north by Ophelia.