Fog and haze are both common weather conditions that can limit visibility, impacting everything from driving to outdoor recreation.
While many people use the terms interchangeably, fog and haze are actually very different. Read on to learn how they form and how to tell the difference between fog vs haze.
Fog: A cloud on the ground
Fog is made up of tiny water droplets hanging in the air. We call it “fog” when you can’t see farther than 1,000 meters (a little over half a mile).
Fog forms when water vapor in the air turns into liquid water. This happens when the air cools and can’t hold as much moisture.
Interestingly, official weather forecasts often use different visibility standards. To aviation forecasters, “fog” means visiblity is less than 1,000 meters. But in public forecasts, it usually means visibility is less than 180 meters (about 600 feet).
What is haze?
Haze is a suspension of dry particles in the air. Unlike fog, haze isn’t made up of water droplets. Instead, it’s dust, smoke, pollution, and other tiny bits of stuff floating around.
Haze often gives the atmosphere an opalescent or milky look.
The particles that cause haze can come from natural events like dust storms and wildfires. They can also come from human activity and pollution.
What’s the difference between fog and haze?
Fog is moisture. Haze is dust.
- Fog is made of water droplets suspended in the air, while haze is made of dry particles.
- When the visibility is less than 1,000 meters, it’s fog. Haze may or may not affect visibility as much, depending on how many particles are in the air.
- The water droplets in fog scatter light more effectively than the particles in haze. That means fog reduces visibility much more drastically.
Frequently Asked Questions
What is the difference between fog and haze?
The key difference lies in their composition and visibility. Fog is made of water droplets or ice crystals suspended in the air, significantly reducing visibility to less than 1 kilometer (0.62 miles). Haze, on the other hand, consists of dry particles like dust, smoke, or pollutants, resulting in reduced clarity but generally better visibility than fog.
What is the difference between fog and mist and haze?
Fog is the densest, with visibility less than 1 km. Mist is lighter, with visibility between 1 km and 2 km, also composed of water droplets. Haze, as mentioned, comprises dry particles and allows for greater visibility than both fog and mist.
Does hazy mean fog?
No, hazy does not mean fog. They are distinct phenomena. Haze implies a general lack of clarity in the air due to the presence of particulate matter, while fog specifically refers to water droplets or ice crystals reducing visibility.
Is haze just fog?
Absolutely not. Haze and fog are different phenomena. Fog is water-based, while haze is caused by dry particles. Fog limits visibility more severely than haze does. The conditions that cause each one to form are also totally different.
Final Thoughts
Although fog and haze may seem similar at first glance, they’re actually quite different. Fog is made of water droplets, while haze is made of tiny particles. Because of this, they affect visibility differently.
Knowing the difference can help you better understand weather reports and make safer decisions when you’re out and about.