Too cold to snow?

 Just found a quote with this explanation 

"This saying is because less cold air (around 0c to 2c at the surface), is usually associated with more frontal activity. Whereas colder temperatures of -5c and below are usually associated with low humidity. This is most true in the UK, where the source of snow is from atlantic moisture and slightly milder temperatures. However in more continental countries, such as eastern Europe and the central northern US, snow occurs more often at colder temperatures."

Which doesn't address polar snow....but it is a start!