The unseasonably warm breeze smelled like bonfires as it blew across the country.
Some even said they could smell sulphur.
Sharon Derrick shared a video of the sun over Bristol and said: "Bristol looks like the film The Red Planet... the weather is bizarre."
One woman wrote on Instagram: "It looks like the apocalypse is coming! Anyone else seen the amazing red sun due to the dust storm from the Azores? That combined with the really warm, strong winds, make it feel very eerie outside today! Keep safe everyone".
So why did it occur?
According to the Met Office, the red sun is caused by winds pulling up Saharan dust.
This dust is then reflected and refracted in longer wavelengths, giving a red appearance to the sky.
Met Office forecaster Grahame Madge said the former hurricane is pulling air and dust up from southern Europe and Africa.
"It's all connected with Ophelia, on the eastern side of the low pressure system air is coming up in the southern direction," he said.
"Air is being pulled from southern Europe and Africa and that air contains a lot of dust.
"So it's most likely the appearance of sunset at midday is caused by the particles scattering the light and giving the appearance of a red sun.
"It's certainly spectacular at the moment and quite a talking point, we've had a lot of calls about it."
BBC weather presenter Simon King 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.
"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.
"Because the dust is so high, light from the sun is scattered in the longer wavelengths, which is more the red part of the spectrum, so it appears red to our eyes."
Ophelia has pulled in unseasonably warm air up from Spain and North Africa, bringing temperatures in the early 20s over the weekend.
Huge forest fires have also swept across central Portugal and west central Spain, killing at least nine people and filling the sky with ash and smoke.
The finer particles of that ash will have already been blown over the Bay of Biscay and is currently filling the upper atmosphere over Bristol and the south west.
The air is safe to breathe, according to the Met Office, as the particles are high up in the atmosphere.
How did people react?
