Yellow is the color of happiness, and gray the color of depression.  Apparently the blues is more actively unhappy, but that wasn’t addressed.  See this study.

It is gray here today.  It is raining now on the weekend’s foot of snow, but is supposed to turn to snow again tonight.

Awaking last night, I discovered “white nights” are the effect of falling snow.  The cloudy sky was much darker than the snowy ground and trees.