What the app shows you
Full FogCast score, fog type, chase-or-skip verdict, and 10-day outlook — all in the app.
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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 StoreNewfound Gap sits at 1,539 meters on the Tennessee–North Carolina border in the heart of Great Smoky Mountains National Park — the most visited national park in the United States, and named directly for the blue-tinted haze and fog that perpetually fills its valleys. The Smokies sit in a moist corridor between the Gulf of Mexico and the eastern seaboard, and the combination of high elevation, dense forest transpiration, and frequent temperature inversions makes valley fog here among the most reliable and photogenic in the eastern US.
Newfound Gap Road (US-441) descending into the Sugarlands valley on the Tennessee side is one of the best fog-chasing drives in the park — the gap itself is often above a fog layer filling the Oconaluftee and Little Pigeon valleys on either side. Clingmans Dome, another 300 meters above the gap, offers views across the full extent of the fog-filled ranges on the best mornings. Autumn, October through December, is the peak fog season, though the Smokies produce fog events in every month of the year.
Smoky Mountain fog is driven by both radiation fog in the valleys and orographic mist rising from the forest canopy itself — the visible blue haze is partly volatile organic compounds from the trees. Check valley temperatures and dew point the evening before: if the Gatlinburg or Cherokee valley temperatures are forecast to drop within 2°C of dew point with calm winds, the higher overlooks at Newfound Gap will very likely be above the fog layer at sunrise.