You've probably noticed drivers using fog lights even when the weather is clear, and perhaps you've wondered: Is it illegal to drive with fog lights on all the time? Fog lights are designed specifically for driving conditions with significantly reduced visibility like fog, heavy rain, or snow. Using them improperly can not only be distracting and unsafe but might land you on the wrong side of the law.

Below, we’ll break down the federal regulations, state laws, and real-world guidance you need to understand fog light legality in the U.S.

Understanding Fog Lights: What Are They Exactly?

Fog lights are specially designed lights typically installed low on the front of a vehicle. Their purpose is to improve visibility when driving through fog, heavy rain, or snow. Unlike regular headlights, which can reflect off moisture in the air and create glare, fog lights cast a wide, low beam that stays close to the road. This helps drivers see the area immediately in front of the vehicle more clearly.

Due to their unique design, fog lights aren't intended to replace your vehicle's standard headlights but rather supplement them during challenging driving conditions.

Further reading:

What Are Fog Lights and What Do They Do?

Fog Lights vs. Headlights: Learn the Difference & When to Use Each

Are There Federal Laws Governing Fog Light Use?

You might be surprised to learn that no federal law in the U.S. specifically forbids using fog lights in clear weather. The key federal regulation—FMVSS No. 108—focuses on the technical standards for vehicle lighting, such as placement, brightness, and design. While fog lights are included in this regulation, they’re not mandatory equipment, and their use on the road isn’t federally controlled.

That responsibility lies with individual states. So, depending on where you’re driving, using fog lights when it’s not foggy could be perfectly legal—or it might get you a ticket. Always check your state’s traffic laws to be sure.

State Regulations: Examples and Comparisons

Let's look at some examples of state-specific regulations to better understand fog light usage laws:

California

California Vehicle Code § 24403 allows up to two fog lamps on a vehicle, but they must be used with low-beam headlights—not in place of them. State code also regulates how high they can be mounted (12 to 30 inches above the ground) and how low the beam must aim (no more than 4 inches high at 25 feet).

Importantly, fog lights can only be used during “darkness or inclement weather”—defined as times when visibility is under 1,000 feet or when windshield wipers are in continuous use. You’re also limited to a total of four front-facing high-intensity lamps, so fog lights can’t be used with high beams or additional lighting.

Florida

Florida also permits fog lamps but limits their use to times when low beams are required. The law doesn’t outright say, “Don’t use them in clear weather,” but it’s implied: fog lights are only legal when low beams are necessary due to poor visibility. Using them alone or when weather doesn’t call for it could be considered improper use.

Minnesota

Minnesota law is similarly strict. According to Minnesota Statutes § 169.56, Subdivision 2, fog lamps must be mounted between 12 and 30 inches from the ground and aimed to avoid glare (no more than 4 inches high at 25 feet). They are only permitted when used with low beams, not on their own or in fair weather.

Common Ground Across States

Most states view fog lights as optional safety features—not general-purpose lighting. They’re generally allowed only in poor visibility, and almost always require low-beam headlights to be on at the same time. To make sure you’re following the law, check your local DMV or state vehicle code.

Why Shouldn't You Always Drive with Fog Lights On?

They create glare, not clarity

Fog lights are designed with a wide, low beam to cut through fog, rain, or snow—not to illuminate clear roads. When used in good weather, they scatter light across dry surfaces and can dazzle oncoming drivers, sometimes even more than high beams. This glare reduces visibility for others and can be distracting or dangerous.

There are legal restrictions

In many places, including the UK and across various U.S. states, fog lights are only legal during poor visibility conditions, such as fog, heavy rain, or snow. Some states require fog lights to be used only with low beams, and only when visibility is significantly reduced.

They can still cause glare even when not directly aimed

Improperly aimed fog lights can reflect off wet roads, signs, or other surfaces—especially at night. This reflected light can confuse or momentarily blind oncoming drivers, which is particularly dangerous during turns or when passing.

It’s unnecessary wear and wasted energy

Even though modern vehicles manage energy efficiently, running extra lights when they're not needed still draws power and can shorten the lifespan of your fog light bulbs. Over time, that adds up to unnecessary maintenance and energy use.

Tips for Proper Fog Light Use

To ensure you're using fog lights safely and legally, consider these tips:

Only activate fog lights during fog, heavy rain, snow, or similar situations where visibility is seriously reduced.

Always switch them off as soon as visibility improves or becomes clear.

Regularly check your state's regulations regarding fog lights to maintain compliance.

Ensure fog lights are properly mounted and correctly aimed; improperly adjusted lights can cause excessive glare, even in appropriate weather conditions.

Also read: When to Use Fog Lights: A Practical Driver’s Guide

"Wipers On, Lights On" Laws: Related Regulations You Should Know

Many states also have what's called "Wipers On, Lights On" rules. This means whenever your windshield wipers are in continuous use due to rain or snow, your headlights must also be on. While this doesn't directly regulate fog lights, it emphasizes the broader principle of proper lighting use under conditions of reduced visibility.

Final Thoughts: Stay Safe and Legal

Although there’s no federal law banning the use of fog lights, many states have specific rules restricting their use. If the weather is clear, it’s best to keep them off.

If your fog lights aren't working or you're thinking about upgrading, consider checking out SEALIGHT’s selection of LED fog light bulbs for a brighter, more reliable option.

Note: This is not legal advice. Always consult your local road authority to confirm what applies in your state or territory.