Home › Weather › Moderate Fog Warning
Live forecasts update automatically; written guidance last reviewed 16 June 2026 by the Metro Report weather desk. Data from national met services via Open-Meteo.
A moderate fog warning, issued by the Met Office, means visibility is likely to fall below 100 metres in places, causing hazardous driving conditions and potential travel delays across the affected region.
What does a moderate fog warning mean for my area?
When a moderate fog warning is in place, expect sudden reductions in visibility, particularly overnight and during the early morning. In coastal areas and river valleys, fog can be especially dense and slow to clear. Drivers should use dipped headlights, reduce speed significantly, and allow extra time for journeys. The warning typically covers a specific timeframe, often 6–12 hours, and may be upgraded if conditions worsen.
How should I prepare for a moderate fog warning?
Check your local forecast before travelling. If you must drive, keep a safe distance from the vehicle ahead and use fog lights only when visibility drops below 100 metres. Pedestrians and cyclists should wear bright or reflective clothing. Airports and ferry services may experience delays or cancellations, so confirm your travel plans directly with the operator.
Is moderate fog dangerous for driving?
Yes. Sudden patches of thick fog can reduce reaction time. The safest advice is to delay non-essential journeys until visibility improves, or use major roads which are more likely to be gritted and well-lit.
Does fog affect flights?
Yes. Low visibility can delay take-offs and landings, particularly at airports without advanced instrument landing systems. Check with your airline before heading to the terminal.
When does fog usually clear?
Fog often lifts by late morning as the sun warms the ground. However, in winter or near large bodies of water, it can persist all day. Coastal fog may linger into the afternoon.
For the latest conditions across the country, visit our UK weather hub or check the 10 day weather forecast for your area.