The woodland path is dry this afternoon. The sky is pure cloudless blue, hardly a breath of wind. How many September Sundays have there been like this, when the air seemed so transparent you could swear voices were murmuring just off east of the hemlocks? But they weren’t, as far as you could tell.

The cats are lazing in the sun on the newly painted deck. Two or three huge dragonflies are floating around the yard, silvery wings and blue-black-banded tails. The last of the flying grasshoppers careen around like little aimless pinwheels. In a corner of the back door frame here deep in spider season Bonnie spotted a huge orbweaver who turned out to be Araneus saevus, a cousin of the barn spider, Araneus cavaticus, the prototype for E.B. White’s Charlotte. When I was coiling the hose, a thin-legged wolf spider darted past a lethargic conifer seed bug into a wall crack.

At the edge of the woods the small birches, poplars, a couple of elderly alders and a cluster of ash trees have dropped hardly any leaves so far. Usually the ashes shed first, and even the deck has much less birch leaf litter than usual for late September. My unprofessional guess is that the August heat, which rolled right into the second and third weeks of this month, gave the trees a false sense of summer. There’s still not much color. But that won’t last even if a few warm days return. Trees read the length of daylight, and the equinox was yesterday, the moment when the sun cuts back across the equator and for six more months all the rays we’ll see are angling in from south. In our yard, south is a line of pointed firs and spruces.

Down at the park, September is unfolding as it always does, intensely. Pastel blue bushy asters line the path, upstaging the fading goldenrod. Deep-violet New England asters bright on the roadside. Delicate yellow blossoms of evening primrose. A few red berries in the brush. Burdock, brown and dry. Those white mystery hemlock-parsleys that look like Queen Anne’s lace but aren’t, boomed in fields this summer and now are dulling down. Wall hawkweed (I think it is) bubbles up yellow all over the expanses of lawn and soccer field. What late-summer energy sends their heads up from the green like little eager faces on the first day of school?

A cabbage white flutters by, and then two clouded sulphurs. They flit and separate; one goes east, the other west toward the soccer field. The east-moving wings swoop up then down, then back, and suddenly the chaotic yellow tandem pops together again beyond the cattails as if they were tethered on a string. There’s no way this kind of beauty is random.

The lake is cobalt blue. So are the blue jays slipping from branch to branch in the woods, uncharacteristically silent. The sky, September blue. This afternoon the purity of autumn is so intense it’s almost more than I can stand.

There’s a story about a man who prayed to see an angel, and finally one revealed itself as a disk spinning 3 or 4 feet above the ground, maybe on a day like this. Dissatisfied, though, the man demanded to see the angel’s real face. The angel told the man he shouldn’t wish for such things. But the man persisted. “Then look,” the angel said. The man screamed as the angel’s face filled the entire sky, its gaze fixed directly on him. “Never let me see a sight like this again!” the man shouted and looked away before the vision killed him.

There are angels this close to your face today. And presumably tomorrow, and everywhere else. Fortunately, they are clothed in September.

Back at the house, I lug in more armloads of firewood, getting ready for the inevitable.

Dana Wilde lives in Troy. You can contact him at naturalist1@dwildepress.net. His recent book is “Summer to Fall: Notes and Numina from the Maine Woods.” Backyard Naturalist appears the second and fourth Thursdays each month.