Weather changes how every other rule in the Highway Code should be applied, from stopping distances to visibility and vehicle control, and this section, generally covering rules 226 to 237, sets out the specific adjustments expected of drivers in rain, fog, snow, ice, and strong wind. It's a heavily tested area because it mixes clear legal requirements, like fog light use, with judgement-based advisory guidance.
Safety margins and hazard awareness questions on the theory test draw directly from this section, and mock test learners often mix up when fog lights must be switched off, which is a strict legal point rather than a matter of preference.
Rain and reduced grip
In wet weather, stopping distances can be double those in the dry, so you should at least double your following distance and reduce speed to account for reduced tyre grip and spray affecting visibility. Standing water can also cause a loss of steering control known as aquaplaning, and easing off the accelerator without braking sharply is the recommended response.
Fog
In fog, reduce your speed, use dipped headlights, and only use front or rear fog lights if visibility drops below 100 metres, which is roughly the length of a football pitch. You must switch fog lights off as soon as visibility improves, because they can dazzle other drivers and mask your brake lights.
- Use dipped headlights, not full beam, which reflects back off fog.
- Increase your following distance and use markings, such as reflective studs, to judge the road ahead.
- Switch off fog lights once visibility is back above 100 metres — this is a legal requirement, not just advice.
Ice and snow
On icy or snowy roads, gentle, smooth inputs on the accelerator, brakes, and steering reduce the risk of skidding, and stopping distances can increase to around ten times the normal dry distance. Check your mirrors are clear and consider whether the journey is necessary at all in severe conditions.
Strong wind
High-sided vehicles, motorcyclists, and cyclists are particularly affected by side winds, so give them extra room, especially near bridges or gaps in hedges where gusts are strongest. Reduce your speed and grip the wheel firmly if your own vehicle is being buffeted.
Frequently asked questions
When am I allowed to use front or rear fog lights?
Only when visibility drops to around 100 metres or less, roughly the length of a football pitch. You must switch them off again once visibility improves, since leaving them on can dazzle other drivers and hide your brake lights.
How much further can stopping distances increase in icy conditions?
Stopping distances can increase to around ten times the normal distance on ice, far more than the doubling seen in wet weather. This makes gentle, early braking essential rather than relying on normal reaction habits.
What should I do if my car begins to aquaplane?
Ease off the accelerator without braking harshly, holding the steering as steady as possible until the tyres regain contact with the road. Braking suddenly can make loss of control worse.
Should I use full beam headlights in fog?
No, full beam reflects off fog and reduces your visibility further. Dipped headlights, and fog lights if visibility is very poor, are the correct choice.
Why do vehicles need extra space in strong winds?
Gusts can push lighter or high-sided vehicles, cyclists, and motorcyclists sideways unexpectedly, particularly near bridges or gaps in hedgerows. Giving extra room reduces the risk of a collision if they're blown off line.