FogCast · Green Mountains, VT
Fog Forecast for the VT Green Mountains
Know before you drive: FogCast checks the conditions that produce photogenic fog
Reading current conditions…
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Fog photography in the Green Mountains
Vermont's Green Mountains run the length of the state, and the steep, narrow valleys between them, especially around Stowe, Waterbury, and the Mad River Valley, are prone to strong overnight fog and temperature inversions. On the best mornings, the valley floor disappears under a solid fog layer while nearby summits and ridgelines sit in clear sun above it.
Mount Mansfield's summit road and the ridgeline along Route 108 are the classic inversion viewpoints, looking down into the Stowe valley as fog fills in below. In the Mad River Valley, farm roads around Waitsfield and Warren catch fog settling over open fields, often with the ridge as backdrop. Sunrise is essential for both, since inversions typically break by mid-morning.
Fall is the strongest season, when foliage color combines with the temperature swings that drive inversion fog. A clear, calm night after a warm day is the setup to watch for. If summit access is possible before sunrise, that's where the sea-of-clouds shot happens.
Other fog photography locations
Why fog is hard to predict
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.
Dew Point Depression
When air temperature and dew point converge below 2°C, the air is near saturation. This is the single strongest fog predictor and the first thing FogCast checks.
Wind Speed
Fog needs calm air. Below 5 km/h is ideal. Above 15 km/h, fog disperses before it can pool in the valley. A standard weather app won't flag this combination.
Overnight Sky Clarity
Clear overnight skies let the ground cool rapidly, pushing surface temperatures toward the dew point. Counterintuitively, clouds overnight suppress radiation fog.
Temperature Trend
FogCast reads the overnight temperature arc. If temps are converging toward the dew point hour by hour, fog probability increases significantly by pre-dawn.
Check today's FogCast
What the app shows you
Set a threshold and get a notifications when fog will form. Never check manually again.
Get LightCast Suite on iOS
Frequently asked
Can I check FogCast on the website?
This page shows a preview of current conditions, including humidity, wind, temperature, and dew point. The full FogCast score, 7-day outlook, push notifications, and best shooting windows are available exclusively in the LightCast app for iOS.
Is FogCast free?
The current conditions preview on this page is free, no account needed. The full FogCast tool is in the LightCast Suite iOS app, which includes a 7-day free trial. After the trial it's $2.99/month, cancel anytime in the App Store.
Why use FogCast instead of checking humidity?
Humidity alone doesn't tell you whether photogenic fog is likely. High humidity with strong wind produces no fog at all. FogCast combines dew point depression, wind speed, overnight sky clarity, temperature trend, and visibility into a single score built specifically for fog photography planning.
What is FogCast's scoring scale?
FogCast scores fog conditions from 0 to 100. A score of 75 or above indicates dense fog is expected. 55 to 74 means fog is likely and worth chasing. 35 to 54 suggests patchy mist is possible. Below 35, conditions are unlikely to produce photogenic fog. The full score is available in the LightCast app.
