The Met Office has predicted that Heathrow airport will get up to half an inch of snow.
Snow may fall on Friday and could cause problems for flights leaving that evening.
Temperatures are also set to stay around freezing for most of the week, meaning airports will have to leave extra time – about 30 minutes per flight – to de-ice planes.
And as this weekend marks the beginning of half term, it’s one of the busiest in the year, with 90,000 passengers expected to use the airport on Saturday.
Other parts of the UK will face around an inch, which will affect airports in cities like Birmingham, Manchester, Leeds and Edinburgh.
Last weekend saw three inches of snowfall over Heathrow, which caused 600 flights to be delayed or cancelled and disrupted 18,000 people’s travel plans.
One pilot described the situation on Saturday night as “carnage”, but the airport says it will be able to cope with the next snowfall.
If the weather gets worse, the airport will have to decide whether to cancel some flights to avoid a backlog.
Forecasters say that freezing conditions will continue in the UK throughout most of February.
Met Office forecaster Steven Keates said: “It looks as if this cold snap will last two or three weeks and this weather system looks as though it will erode from the west in the second half of February.”
Parts of the UK woke yesterday to a second day of snow, closing some schools and causing delays to some public transport.
