Watch CBS News

Why Has It Been So Foggy Lately? Roberta Gonzales Explains

KPIX 5 Morning Weather Anchor Roberta Gonzales answers the questions you never get to ask on-air.

Q: Hey Roberta! Exactly why so foggy? I thought you would enjoy a view off of Skyline Blvd above Woodside. An amazing video for an amazing woman.....have a great day! - Jennifer Heit

A: Aww! You made my day! Thank you for the GORGEOUS video and thank you for thinking of me!

Fog forms when you have the difference between an air temperature and a dew point less than four degrees Fahrenheit. For example, at 9:00 a.m. Tuesday morning, SFO reported an air temp of 55 degrees and the dew point was 52. It was so foggy/cloudy, the airport reported hour-and-21-minute delays on some arriving flights.

The air temperature and the dew point was so close together, because the earth's surface temperature has been cooling, and on top of the earth, we have moist air (from this past Sunday's rain) above it. In addition, we have lacked breezy winds. This is commonly referred to as "radiation rog" or in the Central Valley, "valley fog."

Do you have a question or observation you would like to share with me? I would love to hear from you! Please email

View CBS News In
CBS News App Open
Chrome Safari Continue
Be the first to know
Get browser notifications for breaking news, live events, and exclusive reporting.