Here in the Northeast, where deciduous trees dominate, winter is a time when the full foliage of summer is starkly absent; everything seems harder, more brutalist. And then there's fall - the flightless bird of seasons, ill-fittingly wavering between frigid, damp overcast and vibrant, blustry sunshine.

I won't pretend to delight in fall's foulest weather, as though squalls and frosted mornings cleanse the overheated runner's soul or let the trail aficionado embrace yin-like calm in the face of this karmic weather yang(er). But it offers a transition unlike any other in our training regimes.

I notice it most in that flattening fitness feeling, when my running legs switch from Need To Move to Functionally Underwhelming. The soreness of a 6-month training plan catches up rapidly, and I find myself wondering each day whether a run is really the best use of my precious time and energy.

Almost uniformly it is.

Unfortunate for these prevarications, then, that it's necessarily accompanied by layers of running clothes, each of which must be thoroughly thermally adjustable. Arm warmers, of course, and gloves, then a thin cap, a neck warmer, a zippered wind- and water-resistant vest, and zippered (cycling) tights. Individually, each can be vented or packed away once I'm fully warm or in the sun, or quickly tugged back on for traversing particularly cold valleys or stopping to smell the rotting leaves; as a group, they add 5 minutes to the run prep, enough time to make me wonder about my weird obsession with trails while I wait for the 6:45 sunrise.

But there really is nothing comparable to harvest-time trails. Each year the detritus of fallen leaves and blown-down sticks crescendos in a mesh of layers thick enough to obscure ankle-breakers and mud pits and small ponds. To aid in the runner's adventure, all the markings of the trail/not-trail barrier are punctured: where summer's overgrown branches hung over a noticeable path, barren sticks now jut at odd angles, yielding as little information as possible; and where winter's repeated foot traffic will imprint snow with a dominant route, freshly dropped leaves hold no such memory, such that at any time, an alternate direction might appear as good and leaf-covered as the prescribed one.

Of course I continue to run. Autumn excursions are less carefree than in summer, to be sure, and in many ways I find them more dangerous than in winter, when the bitter cold and snowy or slushy surface are all the warning signs you could ask for. I know deep down that, like the 20 or so years before this, I'll embrace the transition into winter running sometime around the beginning of December. I will accept that those formerly fast-paced daily 10ks will scale back by 20% either in speed or distance; that my long runs won't go quite as long; that I'll spend more time cross-training indoors.

In fall, though, each of these is a hard sell. This morning, in the clearing next to the forest edge on my local trail, I was keenly aware of the soft touch of autumn sun that whispered against my bare wrists and cheeks. I will enjoy this last stretch of vestigal summer, knowing all too well the inevitability of the bone-deep chill that lies in wait.