Dense fog happening along Grand Strand. It’s thicker on beach. Here’s why

The National Weather Service issued a dense fog advisory in areas along the Grand Strand Monday morning.

The fog is common during this time of the year, also known as “sea fog,” said NWS Meteorologist Tim Armstrong. Sea fog occurs when ocean temperatures are colder than air temperatures.

“We had far below normal temperatures for most of the winter, so the ocean water is actually several degrees colder than normal,” Armstrong said.

Warm air from Florida moved in, and temperatures reached into the 70s over the last several days. When humid air touches the cold water, it reaches a condensation point and fog develops, he said.

Armstrong said fog will probably continue through Wednesday. A cold front is predicted to sweep through Thursday morning and the fog will likely dissipate.

Residents right on the beach will be fairly chilly this week due to the cold ocean water, he said, but there will be a significant contrast 10 to 15 miles inland. Those residents could see record temperatures for this time of year on Wednesday, Armstrong said.

How long will sea fog occur?

As ocean temperatures warm, fog generally stays away.

“Once we get into late spring and the course of the summer, the ocean is very warm, and you’re not able to fill those air masses down to the dew point anymore,” Armstrong said.

This story was originally published March 9, 2026 at 10:13 AM.