How much does it snow in -63 degrees celsius?
It can snow even at incredibly cold temperatures as long as there is some source of moisture and some way to lift or cool the air. It is true, however, that most heavy snowfalls occur with relatively warm air temperatures near the ground—typically -9 degrees Celsius (15 degrees Fahrenheit) or warmer—since air can hold more water vapor at warmer temperatures = http://nsidc.colorado.edu/snow/faq.
