Thick fog could sweep over the North West tonight, with visibility falling below 100m in some places.
The Met Office has issued a yellow warning of fog for Lancashire, Blackburn with Darwen, Greater Manchester, Cheshire West and Chester, Merseyside, Halton, Warrington and Cheshire East between 4pm tonight and 6am tomorrow.
Slower journey times are expected, with possible delays to bus and trains services. Some delays and cancellations to flights are also possible.
Fog may start to lift during the night, but some patches may linger throughout the night.