How it works

Each evening Mist Opportunity looks at tomorrow's hourly forecast from two hours before sunrise to two hours after, at several points across your chosen radius. Each hour gets a score out of 100, and the best hour becomes the day's score.

Dew point spread

When the air temperature falls close to the dew point (within 1–2°C), moisture condenses into tiny droplets — fog.

Humidity

Relative humidity of 90% or more means the air is nearly saturated.

Light wind

Calm air (under about 10 km/h) lets a cold, moist layer settle near the ground instead of being mixed away.

Clear night skies

Clear skies let the ground lose heat overnight, cooling the air above it — classic radiation fog.

Forecast visibility

Forecast visibility under 1,000 m is fog; under 5,000 m is mist.

High or rising pressure

Settled, high-pressure weather brings the calm, clear nights fog loves.

Labels

Unlikely 0–29 · Possible 30–54 · Likely 55–79 · Very likely 80–100

A word of caution

Forecasts are estimates. Local terrain matters a lot: valleys and hollows trap cold air, rivers and lakes add moisture, and the coast brings sea fog that behaves differently. Use the score as a heads-up, then trust your local knowledge.