Waukesha County


Fog can be a significant hazard while driving, boating, or flying. Both localized foggy conditions, and especially widespread dense fog, can be hazardous. Some of the worst crashes in the state of Wisconsin have been caused or contributed to by fog.

Fog Terminology:

  • Dense Fog Advisory is issued by your local National Weather Service office when widespread dense fog develops. When this happens, visibilities frequently drop to one-quarter of a mile or less. These conditions make travel difficult. Take extra caution when on the road or avoid driving if possible.
  • Freezing Fog Advisory is issued by your local National Weather Service office when fog develops and surface temperatures are at or below freezing. The tiny liquid droplets in the fog can freeze instantly to any surface, including vehicles and road surfaces. Freezing fog makes driving, boating, flying and other forms of transportation particularly hazardous. Visibilities are typically at or below 1 mile.
Safety Tips for Foggy Driving:
  • Slow down. Whenever possible, leave extra time for a longer commute. Getting into an accident will always take more time and energy than commuting carefully.
  • Drive defenseively. Always leave extra room between your vehicle and the vehicles around you, and stay alert in case other drivers get too close.
  • Use your low-beams. Fog lights, which typically include low-beam headlights, are specifically designed to increase visibility in foggy conditions. High-beams, on the other hand, can be reflected back by fog and impair your vision.


dense fog cautionary driving advice


For further information please see the following:

NWS fog safety information

Traffic and commuter information from 511WI