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 StoreClingmans Dome at 2,025 meters is the highest point in Great Smoky Mountains National Park and in the entire Appalachian Trail system. The summit observation tower gives 360-degree views over the most biodiverse forest in North America, but it is also one of the cloudiest spots in the eastern US — receiving over 1,800 meters of precipitation annually and sitting in cloud or fog more than 200 days per year. Fog at Clingmans is not occasional; it is the dominant weather state.
The summit tower above the spruce-fir forest is the iconic foggy photography location — the concrete tower rising from swirling cloud and mist in the ancient spruce forest is otherworldly. The half-mile paved trail to the summit through the fir forest is spectacular in fog at any time of year. Looking down into the valley arms of the park from above the fog inversion is most reliable from September through November and in early spring before convective cloud builds. July and August produce the most persistent summit cloud and fog but with less dramatic light.
Clingmans Dome fog is mostly orographic cloud — moist air from the Gulf and Atlantic is continuously lifted by the Smoky Mountain ridgeline and condenses at summit level. True valley fog inversion, where Clingmans stands above a cloud sea, requires high pressure, calm winds, and a strong inversion below about 1,400 meters. When the Gatlinburg valley is reporting dense fog and Clingmans has clear skies above, the views from the tower over the fog sea toward the Balsam Range are extraordinary.