quoting Rhetorica, Kelatetía: Dis, Major Belt 1:

Easy, if they're connected globally through fast trade: flu season.

"Flu season". It's funny to think about it right now.

A few days ago I decided I'm going to have four seasons and 6 minor seasons, the first ones marked by astronomy and climate, while the others are more determined by climate and biology (or biorhythms). And the minor season that falls in the last two thirds of nausard "autumn" will be named with that etymology.