Fog that is expected to develop "quite widely" is predicted to hit the area this evening.
The Met Office has issued a yellow warning for several parts of the UK throughout tonight and some of tomorrow.
The weather forecaster says fog is likely to hit areas including Hertfordshire, London and Essex around 8pm on Thursday and last until 12pm on Friday.
People are being warned to expect slower journey times, with delays to bus and train services possible.
There is also a chance of delays or cancellations to flights.
Photo: Met Office
The Met Office said: “Fog and freezing fog patches are expected to develop quite widely on Thursday night, with some of these becoming dense in places with very poor visibility.
“This is most likely to affect parts of central England and east Wales, but other areas are also at risk. Fog is likely to be slow to clear during Friday and may last through the day in some places which may lead to some travel disruption.”
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