Today is foggy because some spots, especially inland where there was moderate rainfall recently, have developed areas of fog. The fog tends to be thicker farther inland where visibility is reduced to less than one mile. This is likely due to the combination of recent rain and calm conditions, which allow moisture to linger near the surface, creating fog. Additionally, weather conditions such as a high-pressure system and changes in wind patterns around the Great Lakes region are contributing to the formation of fog by trapping moisture in the lower atmosphere this morning before the sun comes out later.