Here in the high country the deciduous leaves have turned yellow and are drifting to ground, it happens more-or-less suddenly. Aspens put considerable energy into creating and dispersing seeds, but in fact largely reproduce by sending up shoots from their wide-spreading roots. An entire aspen forest turns yellow at the same time, mostly because all of what look like independent "trees" are in fact parts of one giant organism. Another aspen forest down the road a mile or so may turn yellow a week earlier or later, it is a separate organism.
The summer people are packing up and leaving for AZ, TX, FL or CA - in other words, someplace warm. Meanwhile, the hunters are beginning to arrive, those lucky enough to get tags. This part of the world is busy three seasons out of four: summer camping and touring, autumn hunting, and winter skiing and snowmobiling.
Spring is our down season, not much happens during spring. The year-round residents say winter here is okay but lasts too long, much longer than the three months between winter solstice and vernal equinox that is technically "winter." At a guess I'd say it starts a month early and ends a month late, making it five months long. We're a thousand feet higher than Denver, so long winters are logical, if wearying.