Last week came the days we wait all winter and, frankly, half the summer for. Slanting transparent-gold sunlight, warm chill air, blue sky, Canada geese, leaf and acorn scents.

It’s the most gorgeous weather anywhere in the world. Anywhere I’ve been, at least. Here in northern New England, it starts to gain maturity in mid- to late July, like a great blue heron rising out of a stand of cattails and angling over the woods in the direction of October. One afternoon the sky is suddenly bluer than you remember it being all summer. The air is clearer, and the clouds seem purer white than anything you saw in, say, May. Goldenrod is everywhere, like an emblem. Umbels of Queen Anne’s lace bob like white moons over fieldsides. In August, humidity and overcast sometimes haze the air, but the brightness intensifies, and by the first of September clarity takes over everything and stuns your whole mood into awakening.

October is the time of painted leaves, Thoreau said, and he observed in his essay “Autumnal Tints” that it didn’t always look like this, at least in our eyes. “The autumnal change of our woods has not made a deep impression on our literature,” he wrote in 1856. “A great many who have spent their lives in cities, and have never chanced to come into the country at this season, have never seen the flower, or rather ripe fruit, of the year.” He means the purple grasses, red maples, elms in “great brownish-yellow masses, warm from their September oven,” and the fallen leaves themselves, which he calls the “the acme of the Fall” in mid-October.

That was then; this is now, when the “leaf-peepers” (a literary phrase, if there ever was one) travel north even from Massachusetts to catch the October color. It was Thoreau who coaxed them out. He (along with R.W. Emerson and friends) taught us to look at the autumn woods: “There is just as much beauty visible to us in the landscape as we are prepared to appreciate — not a grain more.” We almost literally owe autumn to him.

Nowadays it pushes further into October and even November than it did in his time. The trees calculate closing time by the shifting length and angles of daylight, which are the same as they were in the 1850s, and also by some sylvan measure of temperature. The acme of color in central Maine now is around early to mid-October, as it was in the 1800s in Thoreau’s Concord, Mass., 2 degrees of latitude or so farther south. It seems to me frosts strike later here than they did even 30 years ago, never mind two centuries ago in Massachusetts. Which, if you ask me, is practically tropical compared to Maine.

From one point of view, this may be a sign of an unwelcome change in overall climate. But from another view, it’s a stretching out of the time we wait for all year. There are afternoons in October when the air is still and the sun is angling across banks of grass, withering goldenrod and leaf-strewn athletic fields, where the whole of natural time seems to crystallize. You feel like the day has converged with every gorgeous fall day that ever was and Thoreau will come traipsing out of the woods with a red maple leaf in his hand and raise it in greeting.

It doesn’t quite happen, of course. At least, not like that. But if your mind takes a certain angle, you can catch the echoes in the clear air and the leaves.

Dana Wilde lives in Troy. His writings on the Maine woods are collected in “The Other End of the Driveway,” available from Booklocker.com and online book sellers. Backyard Naturalist appears the second and fourth Thursdays each month. You can contact him at [email protected]