The thick fog that cancelled more than 100 flights at Wellington airport yesterday has lifted, with blue skies now above the capital.

But as airlines put on extra flights to clear the backlog of travellers trying to get home for Christmas, forecasters warn the troublesome weather could return this evening.

"We've seen a break in the weather now. But there is still very warm, humid air across the North Island, so as we head into the evening tonight, I think the fog will return for a time,'' said MetService duty forecaster John Law.

Mr Law believes the fog will clear by Christmas morning, bringing with it brighter spells, before showers arrive in Wellington by the end of the day.


In the meantime, all scheduled flights have left today and airlines have put on extra flights to try to clear the backlog.

"It's always good when the fog clears and people can get to where they need to go, especially at Christmas time,'' said a spokesman for Wellington International Airport.

"There's a lot of relieved travellers.''

Thousands of travellers had their travel plans disrupted when the low-lying cloud shut the airport down yesterday.