Airports across Britain suffered disruption on Monday as heavy fog led to delays and cancellations for a second day.
Flights to and from London airports were being affected, while foggy conditions in the capital and across Europe were causing problems to airports around the country.
"If you are due to travel today we advise that you check the status of your flight with your airline before traveling to the airport as there may be some disruption to flights," London's Heathrow Airport said.
The Met Office issued a yellow warning for widespread and dense fog across central and southeastern England. It said it expected this to slowly clear by late morning.