Driving in fog, rain and other bad weather in the theory test
Updated •5 min read
Use fog lights only when visibility is seriously reduced, generally when you cannot see for more than 100 metres, and switch them off when it improves. In the rain, keep well back because stopping distances are at least double those on dry roads (rules 226 and 227).
This page goes through the Highway Code's rules for fog, wet weather, ice and snow, wind and hot weather, plus parking in fog. Every rule is from the Highway Code on gov.uk and the rule numbers are given so you can check them. For the stopping-distance figures themselves, see our stopping distances guide.
Fog (rules 226 and 234 to 236)
| Point | What the Highway Code says |
|---|---|
| Headlights | You must use them when visibility is seriously reduced, generally when you cannot see for more than 100 metres (rule 226). |
| Fog lights | You may use front or rear fog lights, but must switch them off when visibility improves (rules 226 and 236). |
| Why not otherwise | Fog lights dazzle other road users and can obscure your brake lights (rule 236). |
| Before entering fog | Check your mirrors, then slow down (rule 234). |
| Fog sign, clear road | Be prepared for a bank of fog or drifting patchy fog ahead (rule 234). |
When driving in fog, rule 235 also says to:
- keep a safe distance behind the vehicle in front, because rear lights can give a false sense of security;
- be able to pull up well within the distance you can see clearly, which matters most on motorways and dual carriageways;
- use windscreen wipers and demisters, and beware of other drivers not using headlights;
- not accelerate to get away from a vehicle which is too close behind you;
- check your mirrors before slowing, then brake so your brake lights warn drivers behind.
Parking in fog (rule 251)
Rule 251 says it is especially dangerous to park on the road in fog. If it is unavoidable, leave your parking lights or sidelights on (gov.uk: waiting and parking).
Wet weather (rule 227)
Rule 227 says stopping distances will be at least double those on dry roads, because your tyres have less grip. In wet weather it says you should:
- keep well back from the vehicle in front, which increases your ability to see and plan ahead;
- ease off the accelerator and slow down gradually if the steering becomes unresponsive, which probably means water is preventing the tyres gripping;
- allow for rain and spray from vehicles making it harder to see and be seen;
- watch for spilt diesel, which makes the surface very slippery;
- take extra care around pedestrians, cyclists, motorcyclists and horse riders.
The two-second gap rule is in rule 126. It says the gap should be at least doubled on wet roads and up to ten times greater on icy roads.
Ice and snow (rules 228 to 231)
- Journey: rule 228 says not to drive in icy or snowy conditions unless your journey is essential, and to allow more time.
- Before you set off: rule 229 says you must be able to see, so clear all snow and ice from all windows, and make sure lights and number plates are clean.
- Distance: rule 230 says to keep well back, as stopping distances can be ten times greater than on dry roads.
- On ice: rule 231 says to drive at a slow speed in as high a gear as possible, and to accelerate and brake very gently.
- Checking grip: rule 231 says that on ice, tyres make virtually no noise, and unresponsive steering may mean your vehicle is losing its grip.
Windy weather (rules 232 and 233)
Rule 232 says high-sided vehicles are most affected by wind, but strong gusts can blow a car, cyclist or motorcyclist off course. This can happen on open stretches exposed to crosswinds, or when passing bridges or gaps in hedges. Rule 233 says turbulence from large vehicles affects motorcyclists, so keep well back from them when they overtake a high-sided vehicle.
Hot weather (rule 237)
Rule 237 says to keep your vehicle well ventilated to avoid drowsiness. The road surface may become soft, or slippery if it rains after a dry spell. If you are dazzled by bright sunlight, slow down and, if necessary, stop.
Practise the rules
The free practice questions let you try these rules in question form, and the test centres page lists centres by city if you are booking.
Check what you remember
Try the free theorytest.ai diagnostic to see whether weather rules are a weak area. theorytest.ai is independent and is not affiliated with the DVSA. Gov.uk does not publish test questions, so we cannot say how many are about weather.
Frequently asked questions
When should you use fog lights?
Only when visibility is seriously reduced, generally under 100 metres. Switch them off when visibility improves (rules 226 and 236).
Can you park on the road when it is foggy?
It is especially dangerous. If it is unavoidable, leave your parking lights or sidelights on (rule 251).
You are driving in rain. Why should you keep well back from the vehicle in front?
Stopping distances are at least double those on dry roads, because tyres have less grip. Keeping back also helps you see and plan (rule 227).
What should you do if the steering feels unresponsive in the wet?
Ease off the accelerator and slow down gradually. Water is probably preventing the tyres gripping the road (rule 227).
How far back should you stay on ice?
Keep well back. Stopping distances can be ten times greater than on dry roads (rule 230).