At the tops of most clouds at mid-latitudes, the temperature is well below freezing, and there is a mix of water droplets and ice crystals that ultimately combine and grow large enough to become snowflakes.
(the temperature; is; well below freezing; L:At the tops of most clouds at mid-latitudes) (a mix of water droplets and ice crystals; ultimately combine; ) (a mix of water droplets and ice crystals; grow; large enough to become snowflakes)
the temperature a mix of water droplets and ice crystals a mix of water droplets and ice crystals
is ultimately combine grow
well below freezing L:At the tops of most clouds at mid-latitudes
large enough to become snowflakes