September, when the light comes back

There is a morning, usually in the second week of September, when the group at the gate is wearing gloves for the first time since April and nobody has said anything about it. The dark is a different dark. It has a floor to it. And when the twenty minutes are up and the path shows itself, it shows itself sharper than it has all summer, because the air has finally dried out and the light has somewhere to go.

This is the note I write every year and I write it because people ask when the best month is, and the honest answer is the one they do not expect.

Summer light is everywhere and belongs to nobody. September light has an edge, and the edge is what you came for.

What changes

• The sun comes up later, so the Night Line starts at a civilised hour and the twenty minutes happen at five, not four.

• The air dries. Summer mornings here are thick, and thick air makes light soft. Dry air makes it hard, and hard light makes shadows, and shadows are what the forest is made of at seven.

• The canopy thins. Not much yet, a few percent, but a few percent of gaps in a canopy is dozens of new shafts on the floor.

• The deer come back to the paths. They spent the summer in the deep understory. In September they are on the lines again, at the edges, watching.

Put those together and the walk to the ridge, which in July is a pleasant grey climb, becomes something else. The trunks throw lines across the path. The mist sits in the hollows instead of everywhere. And the ridge, when you reach it at seven, looks out over a forest with its lights on.

The ridge at seven

The Night Line ends where the others begin: on the ridge above the first bend of the Canopy Line, looking down into it. In summer you look down into a soft green nothing. In September you look down into the shafts. From above they are not columns, they are a field of them, dozens, each one standing on its own patch of floor, and you can watch the whole system switch on as the sun clears the far ridge.

Mara's shaft is the big one, near the bend. From the ridge you can see her group arrive under it. You can see the moment they stop talking. It is the best seat in the forest and it is only there for about six weeks.

The cold

It is cold. Not winter cold, but the kind that finds a gap in a jacket and stays there. The gate at five in September is four or five degrees, and the ridge, standing still, feels like less. Gloves. A hat you do not mind looking foolish in. Something to sit on that is not the ground, because the ground has already given up the day's warmth and has nothing to give you.

Booking it

1. The window is roughly the second week of September to the last week of October. Before that the air is still soft; after it the canopy is bare and the light is a different thing again.

2. Book the Night Line, not the Canopy Line, if you want to see the shafts. You cannot see a field of them from inside one.

3. Book a weekday. The ridge holds eight comfortably and twelve badly, and on a Saturday in October it has held twelve.

If you have already walked it

Walk it again. I say this to people who did the Night Line in June and thought it was the best thing they had done, and they look at me as if I am selling something. I am not. It is a different forest in September. The same line, the same stops, the same twenty minutes at the gate. But the light comes back, and you should be there when it does.