Fog season is usually based in the cooler months (late autumn, winter, and early spring)

Fog is formed when any cloud type makes contact with the ground. In low-lying areas, such as valleys and plains, the fog bank is essentially a cloud formation subject to the same wind and temperature reactions clouds experience in the upper atmosphere.

Below are some tips on how to drive safely when your facing foggy conditions:

  • Watch for foggy conditions and be ready to reduce speed. Don’t assume the

fog will thin once you enter it.

  • Obey all fog-related warning signs.
  • Headlights: Use low-beam headlights and fog lights for best visibility, even in during the day. To check for the best visibility, a driver should flick between headlights and fog lights to gauge visibility with each. This also serves as a warning signal to oncoming drivers.
  • Beware of other drivers who may not have turned their lights on. Turning on your four-way flashers will give approaching vehicles a chance to notice you.
  • Beware of other vehicles on the side of the road. Headlights or taillights ahead of you are not always a good indicator of your position on the road.
  • Avoid passing other vehicles. Don’t stop on the side of the road unless absolutely necessary: Drivers behind you may think your well-lighted tractor-trailer is actually another lane for them to drive.

This map shows the average number of days of fog experienced by areas in the conterminous 48 states, with darker colors indicating more fog. Observe the patterns on this map, noting how common fog is in the area where you live or visit.