"Frost in November to hold a duck, the rest of the winter is slush and muck"
Meaning, if it is cold in November, it will be mild in winter.
"When the wind is out of the east, tis neither good for man nor beast"
Since cold winter weather often arrives from the east.
"In the morning mountains, in the afternoon fountains"
Mountains refers to cumulonimbus clouds, and fountains to the thunderstorms they produce.
"Cold is the night when the stars shine bright"
Since stars shine brighter on cold, clear nights.