On Wednesday, December 12, 2012 12:05:19 PM UTC, ron button wrote:
Excuse my ignorance ,but how much does fog effect minimum temps ?,

Does it act like a cloud blanket obscuring the clear skies above,or does

precipitating rime affect the latent heat factor ? I should know this really

after 60 years observing !

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Both. Fog is just cloud so acts in much the same way to arrest or slow temperature fall. And deposition of rime releases latent heat, ~2800 J/g or 680 cal/g at 0 deg C.

Lots of reports from last night of temperatures dropping when rising out of valleys above the fog.

Stephen.