In article ,
Joe Egginton writes:
Been out for a walk, temps 5c, yet the pavements are turning slippery
and icy?


Clear sky, pavements (and other surfaces) radiating heat. Air
temperature 5C but temperature of the surface below freezing.
--
John Hall
"Acting is merely the art of keeping a large group of people
from coughing."
Sir Ralph Richardson (1902-83)