Is fog still fog at high altitudes or a cloud around a moutain?

Fog is a Cloud at ground level but is there a altitude that a cloud at ground level is not considered fog but a cloud.

I have seen that some 600m (1968 ft) that it can safety be considered a cloud but I can’t find too many sources.

My reason for asking is that I have fog probability calculated and current weather conditions (all local). The easiest thing would be to just to use reference to ground level and not above sea level; but I don’t know if that is what people that live on mountains actually consider as fog or clouds. This will ultimately be in @bjarne integration.

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my gut feeling would be that it depends on where you are. When I’m walking on a mountain at 600m inside a cloud, I would call it fog, but if I’m well below that and have to look up to see it, I would call it a cloud around the mountain. If I would way above that cloud on top of a 1200m mountain, I would call it clouds down there.

but for forecasting I would only call it fog when it is very close to ground level. People doing a trail at 600 m above the ground will probable forgive you if you call a 600m cloud, a low hanging cloud, instead of fog.
Clearly I’ve no scientific answer to your question.

Clarification, this would be at the station location. Mainly for those individuals that live on a mountain. Do you call it fog at 6000ft?

As said it is less work for me to consider it fog at ground level regardless of the elevation above sea level, but I want to be as accurate as possible for those individuals that live at high elevations. I would rather be as correct as possible.

I don’t always agree with the AMS glossary, but, in this case, I do … … which defines it based on ground level, not any other level. So, if the ground is 6,000 above sea level, and there are water droplets suspended in the atmosphere near the ground, it is fog.

Note that AMS is providing a definition for the U.S. … other regions may have their own definitions/practices,


and more descriptions and comparisons Fog - Wikipedia