What the app shows you
Full FogCast score, fog type, chase-or-skip verdict, and 10-day outlook — all in the app.
Get LightCast Suite on iOS
Know before you drive: FogCast checks the conditions that produce photogenic fog
Get more than a snapshot of current conditions. The LightCast app unlocks everything to plan ahead
Humidity alone isn't enough. Wind alone isn't enough. Cloud cover alone isn't enough. Photogenic valley fog requires several conditions to line up at once, and most weather apps don't read them together.
Set a FogCast threshold once. The app will alert you when conditions at your saved locations look promising, so you're not manually checking at 4am.
Don't waste a sunrise drive. Check FogCast before you leave.
Download on the App StoreSan Francisco has one of the most recognizable fog climates of any city in the world. The marine layer that locals call Karl rolls through the Golden Gate and across the city's hills with predictable summer regularity, producing conditions that range from a thin veil over the bay to complete whiteout of the skyline. The city's topography creates micro-climates where fog sits differently on every hill.
Twin Peaks and Corona Heights offer the best elevated city fog compositions, with the fog layer sitting below the summits while the skyline dissolves into mist. Alamo Square gives the Painted Ladies foreground with the skyline behind in various states of fog. The Embarcadero and Bay Bridge see low-lying fog on calm mornings that can be dramatic at blue hour.
Summer is peak fog season, with June through August producing the most frequent and densest marine layer. The fog typically rolls in through the Golden Gate in the late afternoon, fills the city overnight, and burns back out by midday. Early morning catches the densest conditions before clearing begins.