The rumor is out; nothing can suppress it. It’s whispered in the amber-tinged crowns of sycamores and spread by the raucous gossip of southbound geese. The low Sun, casting long shadows even at midday, insinuates it. We feel its breath on our skin; its resonance in our bones like the bronze toll of a bell. Autumn is here.

If spring is the sunrise of the year, autumn is its sunset. It doesn’t matter what time of day you read these words; the sun is setting – setting on A.D. 2009. Since the summer solstice on June 20, when we in East County savored 14 hours and 48 minutes of daylight, planet Earth has completed a quarter of its 584-million-mile voyage around the Sun, engraving an arc onto the black granite of space at 19 miles per second. Astronomical autumn arrives this Tuesday, Sept. 22, when we reach a mark along that arc where our daylight and darkness measure about 12 hours each.

But the darkness must have its season. Earth’s next port of call will be the winter solstice, Dec. 21, when in our Bay Area latitude the Sun graces the sky for a mere nine hours and 32 minutes – the year’s midnight.

If autumn and sunset are vehicles of beauty, they’re also vehicles of dread. The dying of the year, like the dying of the day, awakens an ancient fear: we know what’s coming, and the knowledge underscores our frailty and vulnerability. We’re as capable of reversing the encroaching cold and darkness as a starfish trapped in a tide pool of reversing the ocean’s ebb. “As for the nights,” wrote the poet Archibald MacLeish, “I warn you the nights are dangerous. The wind changes at night and the dreams come.”

We know also, in a remote recess of the soul, that autumn is what we are: transitional creatures, always in the process of becoming something else. The steady-state flow of summer and winter symbolizes an existence of perpetual paradise or desolation. From June through August, from December through February, the landscape is static. Is this the metaphor for humanity? No, we know deep in DNA and we know from experience: the transitional flow of autumn and spring – when before our eyes leaves fall and wildflowers blossom – is the truer metaphor for a creature in whom something is always dying; something else is always being reborn.

“We are symbols, and inhabit symbols,” wrote Emerson. As of this writing, I’ve witnessed nearly 22,000 sunsets. You’d think I’d become blasé, but the opposite is the case. With the passage of time, time becomes more precious, and the symbols of its passage – the seasons of the year; the seasons of the day – more striking. As I approach the transition of my earthly existence into something more ineffable, autumn and sunset gain not only metaphorical power; they gain factual power. Numerical power. The clock is ticking. I’ve numbered the days behind me; ahead, those days are numbered, too. When my number comes up, I’ll be as explicit a metaphor for sunset and autumn as they are for me.

If these musings seem melancholic, be assured: autumn is not the season for the blues; it offers other colors to embrace. Leaves in droves wait to amaze us, spattering creek beds in saffron and scarlet, littering the trail like colossal confetti. Leaves the color of footballs and pumpkins, of sunlight and blood. Let the woods drift into dream, let the moan of wind through wizened limbs be the sound of the forest yawning – while we plot our adventures in chromatic splendor, while we set our alarms and program our coffee pots for the world of wakefulness. Time for us to rise; time for the woods to shine.

Of the many canyons that furrow Mt. Diablo, Mitchell Canyon affords us East County folk one of the loveliest autumn walks around. Mitchell Creek cuts the canyon and feeds a variety of colorful foliage not present in the mountain’s higher and drier elevations. The trail that snakes through the canyon, Mitchell Canyon Road, is also one of Diablo’s easiest tracks – nearly dead level for the first two miles. To get to Mitchell Canyon, take Marsh Creek Road west into Clayton and turn left on Mitchell Canyon Road. Where the road ends is where autumn begins.

May your path be firm and your air bracing beneath a sapphire sky. May every twig on every branch seem more finely etched than in summer’s sweltering air. May maples slipping into sleep seem more alive. For that is the irony: the onset of autumn exhorting the canyon to gather its energy for one final, defiant display.

Sure, winter is coming. But autumn is here.