It's August and I am on my bike. That's true most of the time in warm weather, but it is true almost every day in August, the richest month and the most heartbreaking. A bike is a good place to see August from. I wouldn't miss it.

Out here just beyond the edge of the city is bike country. Long peletons of serious cyclists sweep along the wide shoulders of the county highways every evening, and individual riders pick their way among the slower casual bikers exploring the Gateway and Brown's Creek trails that tunnel through the woods across Mahtomedi and Grant and Stillwater.

I like to ride alone, keeping my own tempo. But I ride hard. My bike is a fancy one, close cousin to the bikes they race in the Tour de France and proof that your toys get more expensive as you get older. It's a wonderful machine, feather-light and nimble. When you push it, the bike leaps forward and the tires emit a rhythmic hiss against the pavement — swoosh swoosh swoosh — with each pedal stroke. Every hard turn of the cranks is a thrill.

I am passed from time to time, usually by riders half my age. But my demographic is well-represented out on the road, too, and a few of them are astonishingly fast. You can spot them. A fringe of gray beneath the helmet, the muscled legs that are strong but not young. Knowing where they've been, they know where they're going. They like a good pace.

It's August and I am on my bike. Summer is in full possession of Minnesota. The air is sultry, the fields and forests lush. The season seems to hang motionless, yet it carries hints of things to come. The birds, passions spent and nests emptied, have gone silent. Ducks and geese are finishing their molts and taking to the air with their young to rehearse for the journey south that lies ahead. The angle of the sun is changing. The farmers' markets groan with the early harvests. Before the month is out clouds of blackbirds will swim across the sky and the warm days will melt into cool evenings.

I'll ride on into September and October, maybe even get out once or twice in the Indian Summer of November, though it is a sad business to ride in those brown and barren days.

Of course, you see a lot from a bike. Last summer I went out one afternoon just after a line of storms had passed, and followed the rain clouds as they headed east. The pavement was wet and steaming. The air was thick. A few miles from home the sky darkened. The storm turned back on itself and came straight at me just as the road turned broadside to it. In seconds I was submerged in a blinding deluge. The wind was tremendous and I had to lean into it to stay upright. Pellets of hail bounced off the roadway. It was glorious. And just when I thought I didn't want it to stop, when I felt that this life is sometimes too amazing for the likes of us unappreciative mortals, it did stop. The sun came out, the wind backed down, and I watched as the storm, which seemed to have made a special detour for my benefit, rushed off to another place.

These days I like the idea of trying to outride the end of summer, though I know it's not possible. Here is what I see on my way: The arc of County Road 7 bending steeply down toward Sunset Lake, where I can descend at more than 30 miles an hour. The farm where they keep two burros. Someone mowing the grass in the small cemetery near the Withrow Ballroom. Emerald oceans of corn and soybeans. Wetlands choked with cattails. A big cattle operation that reminds me of South Dakota, and where the yawning door and loft windows of a barn look like the features of a startled human face. The bridge over Highway 96 on the Gateway Trail where you have to go around the horse droppings, and a little further on, the pasture with the open gate that marks the place where the trail begins to drop and riding feels suddenly headlong and effortless as the forest blurs on either side of you. Windrows of hay, open fields, immense horizons. This huge, beautiful world of ours.

It's August and I am on my bike. This particular August happens to be the one in which the government says I have reached "full retirement age." This information seems unconnected to my actual life. I am not retired. As long as I have my wits about me, I won't be retiring. Too many things to see, places to go, books to write. I am younger than Hillary Clinton or Donald Trump.

I am the same age as Bruce Springsteen.

It's August and I am on my bike and you should see this. A long hill looms. There is so much to take in that it is hard to be alone with my thoughts. Near the crest up ahead an oak towers over the roadway. The late afternoon sun threads though its canopy, casting a filigree of shadow across the lane. I let myself imagine that each leaf is marking the place where it will fall in October. Everything has its season and all good things must end, except for these perfect moments, which are eternal. I have miles to go. Days. Years.

The road rises. My legs ache and my lungs are heaving. I'll be home soon, ready to ride another day. It's August. I am on my bike. I lean forward, come off the saddle, and stand on the cranks.

Swoosh swoosh swoosh.

William Souder's biography of John James Audubon, "Under a Wild Sky," was a finalist for the Pulitzer Prize. His most recent book, a biography of Rachel Carson, was a New York Times Notable Book in 2012 and was also named one of the 25 Best Nonfiction Books of the year. He is currently writing a biography of John Steinbeck, which will be published by Norton in 2019. He is surprised but not dismayed to be turning 66.