The Met Office has issued a yellow weather warning as dense, freezing fog is forecast to envelop part of Wales.
The warning will come into effect at 4am on Tuesday and will last through the busy morning commute in the eastern half of the country, including Flintshire, Powys and Wrexham.
It is also predicted to target southern England, the Midlands and a small part of northern England.
According to the forecast, visibility could be reduced to less than 100 metres in places during Tuesday morning.
"Whilst the fog is expected to gradually lift and thin during the morning some patches could persist until lunchtime in the east," it says.
WATCH: What is freezing fog?
Commuters should prepare for delays on the roads and to rail services.
Flights departing from or flying through the warning area may also be affected.
The afternoon will yield a brief period of bright and sunny weather before heavy rain and cloud target the country to close the week.
Here's what to expect on Tuesday morning where you live:
Cardiff
Swansea
Tenby
Aberystwyth
Wrexham
Builth Wells
