Knowing when to use fog lights is one of those driving basics that’s often misunderstood. Used correctly, fog lights can significantly improve visibility and safety in poor weather. Used incorrectly, they can distract or dazzle other drivers and even land you with a fine.
This guide explains when to use car fog lights, why it matters, and the key differences between front fog lights and rear fog lights, so you know exactly when (and when not) to switch them on.
When to use fog lights, and why this is important
Fog lights are designed to improve visibility in severely reduced visibility conditions, such as fog, heavy rain, or snow.
Unlike standard headlights, fog lights are positioned and angled to cut through low-lying fog and reduce glare.
Understanding when to use fog lights is important for two main reasons:
Safety: They help you see the road and allow other drivers to see you sooner.
Compliance: Using fog lights incorrectly can be dangerous and, in some cases, illegal.
As a general rule, fog lights should only be used when visibility drops below 100 metres. If you can see further than that, fog lights are usually unnecessary and may cause glare for other road users.
Before winter driving or long journeys, it’s also worth checking that all your lights are working correctly as part of a routine inspection. Our vehicle inspection checklist covers lighting checks alongside tyres, fluids, and other essentials.
When should you use front fog lights?
Many drivers are unsure when to use front fog lights, but their purpose is very specific.
What front fog lights are for
Front fog lights sit lower than standard headlights and cast a wide, flat beam across the road surface. This positioning helps reduce the amount of light that reflects into your eyes in foggy conditions.
When to use front fog lights
You should use front fog lights when:
Visibility is significantly reduced by fog, heavy rain, or falling snow.
Standard dipped headlights don’t provide enough forward visibility.
Road conditions make it difficult to see lane markings or the road edge.
Front fog lights are most effective when used with dipped headlights, not on their own.
When not to use front fog lights
Do not use front fog lights when:
Visibility is good or only slightly reduced.
Driving in clear weather or light rain.
Following or approaching other vehicles closely.
Using front fog lights unnecessarily can cause glare and confusion for other drivers, particularly at night.
For more cold-weather driving advice, including lighting checks and visibility tips, see our winter safety checklist.
When should you use rear fog lights?
Knowing when to use rear fog lights is arguably even more important, as misuse can seriously affect other drivers.
What rear fog lights are for
Rear fog lights are much brighter than standard taillights. Their sole purpose is to ensure your vehicle is clearly visible from behind in very poor visibility.
When to use rear fog lights
You should only use rear fog lights when:
Visibility is less than 100 metres.
Fog, heavy rain, or snow makes it hard for vehicles behind to see you.
You are driving on faster roads where early visibility is critical.
Under these conditions, rear fog lights can provide approaching drivers with valuable additional reaction time.
When not to use rear fog lights
Rear fog lights should be switched off:
As soon as visibility improves.
When driving in traffic where vehicles are already close behind.
In rain or mist that does not significantly reduce visibility.
Using rear fog lights when they’re not needed can be dazzling and distracting, increasing the risk of rear-end collisions.
Front vs Rear Fog Lights: Key Differences
Feature | Front Fog Lights | Rear Fog Lights |
|---|---|---|
Purpose | Help you see the road | Help others see you |
Brightness | Similar to dipped headlights | Much brighter than the taillights |
Position | Low at the front of the vehicle | One or two lights at the rear |
Common misuse | Left on in clear conditions | Left on after fog clears |
Understanding these differences helps ensure you’re using the right lights at the right time.
Using fog lights responsibly
Knowing when to use fog lights, front fog lights, and rear fog lights is a simple yet essential part of safe driving. Used correctly, fog lights improve visibility and reduce accident risk. Used incorrectly, they can create hazards for other road users.
If you manage a fleet or drive regularly for work, incorporating the use of fog lights into your driver safety guidance can improve compliance and reduce incidents, especially during the winter months.
If you’d like advice on vehicle safety, inspections, or fuel solutions for your business, feel free to get in touch with our team.
