WEATHER FOLKLORE: "Cold is the night when the stars shine bright" APPLICABILITY: Lore applies to middle and high latitude locations, especially in winter. Statement also applies to dry high altitude locations. ANALYSIS AND INTERPRETATION: In the winter, the nights are long in the middle and high latitudes. When the sun is not out, the earth's surface can continually cool off. If the stars are shining bright it means there are clear skies. Clear skies allows radiation emitted from the earth's surface to escape into space. Cloudy nights are warmer than clear nights, all else being equal. Clouds will insolate the lower troposphere, causing the temperature to not cool off as much at night. Interior high altitude locations tend to be climatologically dry. Water vapor acts as a greenhouse gas. When water vapor presence is low, temperatures will cool off significantly at night under clear skies. Also, the thin air at high altitude locations allows more radiation to escape from the earth's surface as compared to a location closer to sea level. |