Cold enough for you?
Here are some interesting facts about winter weather.

WaterFreeze – Shallow areas of a body of water freeze before deeper areas. The deeper the water, the longer it takes to change its temperature. Water reaches its densest state at 39 degrees F. (4 degrees C).

IceCloud – In winter, low temperatures and water vapor in the usually cloudless stratosphere trigger the formation of ice clouds.

LightRays – Although the Sun is at its closest point to Earth at this time of year, Northern Hemisphere temperatures remain cool due to the Sun’s low angle and the amount of atmosphere through which its rays must travel before reaching Earth’s surface.

ColdFront – In winter, cold fronts move at speeds from 10 to 50 knots – two to three times faster than in the summer. If preceded by a squall line, a cold front brings heavy precipitation, usually followed by several days of clear, cool weather.

LightShine – Snow reflects up to 95 percent of the sunlight or moonlight that shines on it, whereas the Sun’s reflectivity on open water is only 10 to 15 percent.

Snowfall – The probability of snowfall depends on geographic factors (elevation and latitude) and season. Upper regions of some mountains have permanent snow cover, a result of the quantity of snowfall, wind types and the slope of the land.

HeatFree – Clear nights are coldest, as there is no cloud cover to keep Earth’s heat from rising into the sky.

Windchill – The faster the wind draws heat from a surface, the more energy is required to replace the heat.

Thanks to Chris Hardman’s Ecocalendar for the above facts. www.ecocalendar.info.