The phenomenon is caused by a regular rainbow and a sunset happening at the same time.
A rare pink rainbow was spotted in the sky over Bristol, England
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Rainbow clouds spotted in the East for first time since 2016 - BBC
Rock pooler discovers a stunning Rainbow Sea Slug in south
Pink rainbow appears over England's south-west - ABC News
Incredible optical illusion sees pink rainbow light up sky
Rare 'pink rainbow' spotted in sky over Bristol
Rare rainbow-coloured nacreous clouds seen across Yorkshire - BBC News
Rare pink rainbow appears in the sky over south west England