FogCast · Lassen Volcanic National Park, CA

Fog Forecast for Lassen Volcanic NP

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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  • 📈 Full FogCast score (0–100)
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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
FogCast score and forecast in LightCast app FogCast score and forecast in LightCast app

Full FogCast score, fog type, chase-or-skip verdict, and 10-day outlook — all in the app.
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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.

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Fog photography at Lassen Volcanic National Park

Lassen Volcanic National Park sits at the southern end of the Cascade Range in Northern California, where Lassen Peak rises to 3,187 meters above a landscape of hydrothermal features, alpine lakes, and dense conifer forest. The park straddles the boundary between the maritime-influenced north and the drier Great Basin to the east, giving it a climate that produces fog from multiple mechanisms — advection fog from the Sacramento Valley, radiation fog in the lower valleys, and orographic cloud wrapping the summit.

Manzanita Lake near the park entrance is the premier fog photography location. The lake sits at 1,756 meters and reflects Lassen Peak when fog layers settle below the summit, creating iconic composite images of the volcano and its reflection through mist. Reflection Lake and Summit Lake are secondary options. The hydrothermal areas at Bumpass Hell and Sulphur Works produce their own steam that visually blends with morning fog in cool conditions. October through December is the strongest fog season before winter snow closes the main road.

Lassen fog is most reliable when Sacramento Valley air masses move upslope overnight and stall below the volcanic rim. Watch for calm northwesterly flow and strong overnight cooling at the valley stations below the park. If the dew point gap at Manzanita Lake is less than 2°C at midnight, lake fog and valley-edge mist are highly likely by 5am.



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.