There is a loop near me, maybe three and a bit miles, that runs out along a hedge line, drops into a wooded strip beside a drain, and comes back up a farm track. I have walked it more than any other route. For one summer I walked it early, before seven, because that was the only window I had. Then my hours changed and I started walking it after four instead. I assumed it would be the same walk in different light. It was not close.
I want to be careful here, because a lot of writing about this turns into something mystical about dawn. I do not think there is anything mystical about it. There are practical differences, and some of them cut against the early morning.
The ground is a different surface at each end of the day
This was the biggest one and I did not expect it. Early, the grass along the hedge is soaked, every time, even after a dry week. By the end of the first field my boots were wet through and stayed wet. In the afternoon the same grass is dry and I finish with dry feet.
That sounds trivial. It is not, if you are doing this two or three times a week. Wet feet for two hours is fine. Wet feet for two hours, twice a week, for a season, is how you end up with your boots never fully drying out and eventually falling apart at the seam. I went through a pair faster than I should have and I am fairly sure the morning dew is why.
Clay tracks work the opposite way. A rutted track that has had all day in the sun is firm by afternoon and greasy first thing. So the surface question is not simply better or worse in the morning, it depends what you are walking on.
Animals move at the ends of the day, and that cuts both ways
Early, I saw more. Deer at the edge of the wooded strip most weeks, hares in the stubble, a barn owl working the same field three mornings in a row. In the afternoon I see almost none of that. The wildlife argument for early walking is real and I am not going to pretend otherwise.
But livestock also move at the ends of the day, and that is less charming. Cattle get brought in or turned out around the same hours I want to be walking. I have twice found myself in a field with a herd that was being moved, which is not dangerous exactly, but it means standing at the fence for ten minutes waiting, and it means I am in the way. Afternoon walks have less of that in my experience, though it depends entirely on the farm.
The afternoon walk gets cut short more often
Here is the thing that actually decided it for me. A walk before work happens. Nothing has come up yet. Nobody has called. There is no reason to shorten it.
An afternoon walk is competing with everything that has piled up during the day. I noticed that my afternoon version of the loop was consistently shorter, because I was cutting the wooded section and coming back up the track early. Not once or twice, most times. I was doing the same route on paper and about two thirds of it in practice.
That is not a fact about light or weather. It is a fact about how a day fills up. If the goal is to actually walk regularly, the morning wins for reasons that have nothing to do with the walk itself.
Light matters, but not the way photographs suggest
Low light is nicer to look at. That is true and obvious. What I did not appreciate is how much low light changes what you can see of the ground.
Walking east into a low sun on a rutted track, I could not see the ruts. Everything was flattened into glare and I turned an ankle in a hole I would have stepped over at noon. Now I think about direction of travel against the sun when I plan the order of a loop. On that particular route I go clockwise in the morning and counter clockwise in the afternoon, purely so the low sun is behind me on the rough section. It is a small adjustment and it has stopped the ankle problem completely.
Midday is underrated and I ignored it for years
I had absorbed the idea that walking in the middle of the day is the worst option: flat light, hot, nothing moving. Some of that is true. But midday is when the ground is at its most predictable, when you can see exactly what you are stepping on, and when a route you have not walked before is easiest to figure out.
So I now do my scouting at midday deliberately. If I am going to find out whether a track connects to a lane, I want the best visibility I can get and no time pressure at either end of the walk. Once I know a route, I move it to whatever hour suits. But learning it happens in flat, boring, useful light.
What I would actually recommend
Pick the hour you can protect, not the hour that sounds best. If your mornings are free and quiet, walk in the morning and accept wet feet as the cost. If your mornings are chaos, do not set yourself up to fail at dawn walks and then feel bad about it. Walk at four and know that you will sometimes cut it short.
The one thing I would say is worth doing regardless: walk the same route at both ends of the day at least once. Not for the scenery. For the surface, the sun angle, and the honest question of whether you actually get out the door. I only learned any of this because I ended up doing it by accident.