FogCast · Mount Adams, WA

Fog Forecast for Mount Adams

Know before you drive: FogCast checks the conditions that produce photogenic fog

Reading current conditions…
Current Conditions
Fog Potential:
Humidity
Wind
Temp
Dew Point Gap

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Mount Adams stands at 3,742 meters in the Gifford Pinchot National Forest in southern Washington, the second-highest peak in the state. Its massive glaciated bulk rises above the forested valleys and meadows of the Yakima and Klickitat drainages, and when fog fills those valleys on autumn mornings, the white volcano stands in stark relief above the mist — one of the great above-fog volcano views in the Cascades.

The Bird Lake and Takhlakh Lake areas at around 1,300 meters on the west and northwest flanks offer the most accessible and most photographed above-fog views, with the lake in the foreground and Adams rising through clearing mist. Horseshoe Meadows and the Divide Camp area give higher elevation perspectives on summit fog and lenticular cap clouds. The Yakama Nation side to the east is more remote but offers vast open views when valley fog fills the plateau below. September and October, before snow closes forest roads, are the prime months.

Mount Adams fog is almost always valley origin — cold air drains from the high slopes and pools in the forest floor valleys, reaching saturation in the early morning hours. The most photogenic conditions occur when fog fills only to about 1,100 meters elevation, leaving the lower flanks and lakes in fog while the summit and glaciers are brilliant in the clear pre-dawn sky. Light winds are essential — any sustained breeze above 15 km/h mixes the valley air and prevents fog formation.



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

FogCast score and forecast in LightCast app FogCast score and forecast in LightCast app

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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.