Suddenly Springtime: the Nonlinearity of Seasons

Why does a change in the seasons always seem to creep up on us? Winter has a way of seeming like it'll never end, like every day closer to springtime brings only another minute of sunlight--and then, nearly all at once, you're enjoying a sunset at 7 PM in nothing more than a light jacket.The official move from one season to another is marked by the solstices--the longest and shortest days of the year--and the equinoxes, days of roughly equal light and darkness...but the way that things change be...