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 StoreZhangjiajie National Forest Park in Hunan Province contains the pillar landform that inspired the floating mountains of Pandora in the film Avatar — thousands of sandstone columns rising up to 200 meters from the forest floor, some with vegetation clinging to their vertical sides, others topped with pine trees. When fog fills the valleys between the columns and the columns themselves emerge from white cloud at dawn, the landscape becomes completely unreal — a visual experience that cannot be adequately described and that fog makes genuinely surreal.
The Yuanjiajie Scenic Area with the Avatar Hallelujah Mountain viewpoint and the Tianzi Mountain area are the top fog photography zones. The glass-floored Zhangjiajie Glass Bridge with its views down into fog-filled chasms is exceptional in the right conditions. The ten-kilometer-long Grand Canyon of Zhangjiajie fills with fog from the valley floor at dawn, leaving only the column tops visible. October and November are the most reliable fog photography months; the subtropical climate with high year-round humidity means fog is common but autumn's cooler temperatures produce the longest-lasting and most dramatic events.
Zhangjiajie fog forms when moist subtropical air condenses in the sandstone column valleys on cool nights. The columns' height and density create sheltered microclimates where fog pools and persists long after it would clear elsewhere. On mornings when the relative humidity in the valley bottom exceeds 92% at midnight and temperatures are below 15°C with no wind, a dense fog filling the lower 50 to 100 meters of the column field is almost certain by dawn. The fog here can move dramatically — streamers of mist flowing between the columns are as photogenic as still fog.