What areas in North America are strongly affected by cloud cover? The main controls on cloudiness are:
synoptic variability from day-to-day
topographic effects
diurnal effects
land albedo gradients, most importantly the sea-land breeze contrast
Sky islands in US/Mexico
California coastal cloudiness and rain shadows
Appalachian Mtns
sea breeze effects Florida and Yucatan
Mexican dry valleys
Central American details