Let’s break down how fog forms. According to the National Weather Service, there are five different types of fog: radiation fog, advection fog, freezing fog, evaporation fog, and hail fog.

Though forecasters warned earlier this week that foggy conditions could combine with smoke from a marsh fire burning in St.

Radiation Fog: This is the most common type. The ground cools rapidly at night, losing heat to the sky. This cools the air layer closest to the ground, causing water vapor in the air to condense ...