Dense fog has cut visibility below half a mile across Collier County, with the Weather Service urging caution on I-75 until 9 a.m.

Patchy dense fog is reducing visibility across coastal and inland Collier County on Tuesday morning, according to a Special Weather Statement from the National Weather Service office in Miami.

The office observed the fog shortly before issuing the statement at 7.23 a.m. It said visibility may fall below half a mile at times.

The statement remains in effect until 9 a.m. and specifically urges motorists to use caution on portions of I-75. It does not identify a narrower stretch of the interstate.

Fog can thicken and thin quickly. Drivers should reduce speed before entering a fog bank and leave more distance between vehicles.