Okay, the seasons. Where do they get their names?
Let's start with spring. The name comes from springing time, as in "plants begin to rise." Speaking of springing things, the Old English spring also meant "carbuncle, pustule."
Summer comes from Old English sumor, from PIE root sem, "summer."
The word fall is similar to spring, as in it comes from "fall of the leaf." Autumn, from Old French automne, from Latin autumnus, is of unknown origin. One possibility is an Etruscan word that means "drying-up season."
Winter, from Old English winter, is from Proto-Germanic wintruz, "winter," probably literally "the wet season," from PIE root wed- "water, wet."
What about countries that have different kinds of seasons? What are they called? Hmm, must research this at some point. This would be gold for world-building, because making up names of seasons would be more fun if they had this kind of a logic to them.