If you’ve ever driven through thick fog and wondered whether your fog lights are helping or making things worse, you’re not alone. One question keeps popping up among drivers: should fog lights be yellow or white?

It’s a topic of ongoing debate, and the answer isn’t as simple as picking the brighter color.

In this guide, we’ll walk you through the key differences between yellow and white fog lights, how they affect visibility, and which color might suit your driving needs better. We’ll also touch briefly on blue and purple fog lights—and why they’re not recommended for practical use.

The Role of Fog Light Color in Visibility

Fog lights come in different colors, driven by their color temperature, measured in Kelvins (K). Lights rated at 3000K produce a warm yellow output, while those in the 4300K to 6000K range emit a cooler, white to bluish-white hue. The choice of color temperature has a direct impact on visibility in foggy conditions.

People also read: Xenon HID Color Chart - Guide to Choosing the Best Headlight Color

To understand why certain fog light colors work better in bad weather, we need to look at how light behaves in fog.

The Science Behind Visibility in Fog

Light Wavelength and Scattering

Light travels in waves, and each color has a different wavelength. For example, yellow light has a longer wavelength (around 570–750 nanometers), while blue light is much shorter (400–495 nanometers).

Fog consists of water droplets that are about the same size as the wavelengths of visible light. When light hits these droplets, it scatters in all directions. This is called Mie scattering—and unlike Rayleigh scattering (which gives us a blue sky), Mie scattering affects all visible light colors relatively equally. That’s why fog often looks white or gray: it’s reflecting a broad spectrum of light.

Why Color Still Matters: Glare and Backscatter

Here’s the key point: while Mie scattering doesn’t favor one color over another dramatically, shorter wavelengths (like blue or violet) tend to cause more glare when scattered back toward your eyes—called backscatter. This can create a blinding “veil” effect, reducing how well you can see.

Yellow light avoids this problem. By filtering out blue wavelengths, yellow fog lights reduce backscatter and glare, allowing your eyes to focus better on the road.

Eye Comfort and Visual Contrast

Our eyes also find yellow light more comfortable, especially in stressful conditions like fog or rain. It reduces fatigue and increases contrast, making objects easier to see against a foggy background.

Yellow Fog Lights

Yellow fog lights are often referred to as selective yellow—a specific tone defined by SAE and UNECE standards. Unlike amber, selective yellow removes most blue and violet wavelengths, leaving a soft golden hue (around 2500K–3000K).

Contrary to popular myth, yellow lights don’t "cut through" fog better in a physical sense. Rather, they reduce glare and make it easier for your eyes to distinguish objects—especially when visibility is already poor.

Why Do Yellow Fog Lights Work Better?

Since fog droplets scatter all visible light similarly, yellow doesn’t penetrate fog better by physics alone. But by filtering out harsh blue wavelengths, yellow fog lights reduce the glare that blinds you. This visual relief helps improve contrast, sharpens edges, and eases eye strain.

If you frequently drive in rural, mountainous, or coastal areas where fog is common—or in snowy, rainy weather—yellow fog lights can significantly improve your driving experience.

Downsides of Yellow Fog Lights

However, yellow lights typically produce fewer lumens than white lights, so they’re not as bright in clear conditions. And while some drivers love the warm, classic glow, others feel yellow lights look outdated compared to the sleek appearance of modern white LEDs.

Are Yellow Fog Lights Legal?

Yes. U.S. regulations under FMVSS 108 allow fog lights to emit either white or yellow/amber light. Blue, red, green, or other colors are not street legal in most states.

White Fog Lights

Most modern vehicles—especially those with LED or HID systems—come equipped with white fog lights. These lights typically have color temperatures between 5000K and 6000K, closely mimicking daylight.

Advantages of White Lights

White fog lights provide a clean, crisp view of the road. They pair well with white headlights and give vehicles a unified, modern look.

Drawbacks in Poor Weather

In fog, rain, or snow, however, white light’s higher intensity and shorter wavelengths tend to scatter more, especially back toward the driver. This can create glare and reduce visibility in heavy fog.

Are White Fog Lights Legal?

Yes. White fog lights are legal on public roads across the U.S.

Yellow vs. White Light in Fog Conditions

Contrast metrics measure how clearly a pedestrian stands out against the road. Higher values = easier to spot. 

Previously, we examined how light behaves in fog and why contrast is crucial for visibility. Some findings from a research into adaptive headlights back this up.

The research focused on how warm (3000K) and cool (6000K) light colors affect pedestrian visibility in fog, rain, and clear nights.

Here are some simplified results:

Takeaway:

In foggy or rainy conditions, yellow-tinted headlights (3000K) generally offer better visibility by reducing glare and improving contrast. However, in clear conditions, white light (6000K) offers brighter and broader illumination.

What About Blue or Purple Fog Lights?

Blue Fog Lights

Blue fog lights have a high color temperature and sit in the 380–500 nanometer range. They offer a high-tech, modern look that some drivers love. They are typically LED or HID bulbs and emit a cool and bluish-white tint.

For many drivers, the primary advantage of blue fog lights is that they provide a modern look and unique appearance.

The biggest drawback of blue fog lights is that they reduce your visibility in bad weather like fog, rain or snow. They are easier to scatter and create glare.

On top of that, blue fog lights are often not street-legal.

Purple Fog Lights

Purple fog lights are more of a novelty than a functional choice. Like blue lights, they scatter heavily in fog and provide little to no practical benefit when visibility is low. Their use is typically limited to car shows or custom displays, and they are usually illegal for on-road use.

Comparison: Which Fog Light Color Is Best?

How to Choose the Right Fog Light Color

So, Yellow or White?

If you regularly drive in dense fog, snow, or heavy rain, yellow fog lights are the better choice. They reduce glare and make it easier to focus on the road in poor visibility.

If your area sees mostly clear conditions and you prefer a clean, bright appearance, white fog lights are a solid option.

Blue and purple lights are mostly cosmetic and come with legal and safety downsides. They're best left for custom builds or shows.

LED vs. Halogen: Which Tech Is Better?

Modern LED fog lights offer several advantages: longer life (up to 50,000 hours), higher efficiency, and better brightness. However, if they’re not properly aimed or installed, they can scatter light inefficiently—especially in fog.

Halogen fog lights, while more affordable, burn out faster (typically under 2,000 hours) and are less energy-efficient. But they naturally produce warmer light, which works well in poor weather.

People also read: LED vs Halogen Headlights Bulbs: What's the Difference?

Best Solution: SEALIGHT LED Fog Lights

For drivers looking to upgrade, SEALIGHT Yellow LED fog lights combine performance with safety. They’re engineered to provide:

Bright and even illumination for all weather conditions
Long lifespan and durability
Easy installation for most vehicles

Whether you're navigating foggy mountain roads or just want a stylish, safe upgrade, SEALIGHT has both yellow and white fog light bulb options to suit your needs.

Last Words

The “best” fog light color depends on your environment. Yellow fog lights shine in tough weather, offering better contrast and reduced glare. White fog lights offer a clean, modern look and perform well in clear conditions. Blue and purple lights may turn heads—but they fall short when it comes to safety and legality.

Have you tried yellow or white fog lights? What’s your experience driving in fog or rain?

Drop your thoughts in the comments—we’re always interested in real-world insights from fellow drivers.