All toolsCloud & Phenomena Identification

Fog vs Haze Distinguisher

Tell meteorological fog from industrial haze using humidity, visibility, and dew-point spread.

Live tool

Temperature (°C)Dew point (°C)

Relative humidity %Visibility (km)

Classification

Fog

RH near saturation and visibility under 1 km.

Dew-point spread: 1.0 °C

Introduction & principle

Meteorological fog requires relative humidity near 100% with visibility under 1 km. Haze is dry aerosol and persists at lower humidity. The tool compares your readings against WMO fog and haze thresholds.

Tool advantage

Civilian air-quality apps lump fog and haze together. This tool separates them so observers can log conditions correctly.

Detailed usage guide

1Enter temperature, dew point, relative humidity, and visibility.
2Read the classification: fog, mist, haze, or clear.
3Use the breakdown to understand which threshold drove the result.

Common problems & FAQ

What if humidity is 95% and visibility is 3 km?

Reported as mist. True fog requires under 1 km visibility.

Related tools

Atmospheric Transparency Query

Estimate local atmospheric transparency for astronomical and meteorological observation.

Open

Temperature & Humidity Converter

Convert between °C, °F, K and between absolute, relative, and specific humidity.

Open

Weather Map Legend Explainer

Explain professional icons and legends used on surface and upper-air weather maps.

Open