Home › Weather › Moderate Fog Warning
Live forecasts update automatically; written guidance last reviewed 16 June 2026 by the UrbanMixr weather desk. Data from national met services via Open-Meteo.
A moderate fog warning (Met Office yellow) means visibility could drop below 100 metres in places, making driving, flying and ferry crossings hazardous. Check local conditions before travelling, especially on motorways and near coasts.
What does a moderate fog warning mean for my journey?
Visibility is reduced enough to disrupt road, rail and air travel. Delays are likely on the M25, M1, M6 and other major routes, particularly during the morning rush hour. Airport operators may hold departures or divert inbound flights. If you must drive, use dipped headlights, leave double the usual stopping distance and allow extra time. Fog often clears by late morning but can linger in valleys and near rivers.
Which areas are most affected?
Yellow fog warnings typically cover inland areas of England, the Midlands, East Anglia and south-east Scotland. Coastal fog can also affect ferry services to the Isle of Wight, the Channel Islands and Northern Ireland. Check the moderate rainfall warning page for overlapping alerts, and see the 10-day forecast for when fog is expected to lift.
Should I cancel my journey because of a moderate fog warning?
Not necessarily. If you can delay travel until after 10 am, fog often clears. If you must go, allow extra time, reduce speed and use fog lights. Check your airline or ferry operator before setting off.
Is fog dangerous for pets or livestock?
Yes, fog can disorient animals. Keep dogs on leads near roads and ensure livestock have clear access to shelter. The RSPCA advises avoiding early-morning walks in dense fog near traffic.
How long does a moderate fog warning usually last?
The Met Office issues these warnings for a specific day or overnight period. Fog typically forms after midnight and lifts by mid-morning. Persistent fog can last into the afternoon in sheltered spots.