Most anglers plan their season around summer: longer days, warmer water, and the kids are out of school, and we all know nothing gets done at work in the summer. So it’s the natural time to hit the water. But ask folks who fish South Platte fly fishing every week of the year, and September is the month they quietly look forward to most.
The Crowds Thin Out
What happens to the South Platte once Labor Day passes?
The shift starts with the crowds. Labor Day marks the turning point on this river, and once it passes, the drift boats head home and the weekend lines at all the local spots start to disappear. Runs that were shoulder-to-shoulder in July open back up, and you can wade a stretch twice without someone stepping in behind you. For a guided trip on private water, that shift matters less, but if you’re fishing public access on your own, September buys you back the river.
The Hatches Come Back to Life
Why does September dry fly fishing rival summer?
As the crowds thin, the bugs come back to life along with the quiet. Blue-winged olives return in force and hold through November. The trico hatch, still going strong from summer, keeps mornings interesting into the month, and warm afternoons still bring hoppers and ants along the banks. Dry fly fishing gets good again, right when most people assume the season is winding down.
Brown Trout Get Aggressive
Why do brown trout turn combative in September?
Then there’s the real draw: brown trout get aggressive. As they stage for the fall spawn, they shift from cautious to combative. Fish that spent the summer sipping midges start chasing streamers through the deep runs. Swing a Woolly Bugger or a Slump Buster through the right water in low light, and you’ll feel the difference immediately. Bigger fish, more attitude, better odds than you had in the heat of summer.
Flows Settle and Sight Fishing Improves
What changes about the water itself in September?
Flows settle out this time of year too, and the water clears up. Wading gets easier, sight fishing gets better, and the fish get a little more selective in return. Come with a range of fly sizes, especially on the BWOs, and be ready to go small when the light’s bright and the water’s low.
A Short Window Before Winter
How long does this September window actually last?
None of this holds forever. Streamer fishing keeps building into October, but the spawn changes how anglers need to approach staging fish and redds, and winter isn’t far behind. September gives you the best combination of thinned-out water, aggressive fish, and manageable weather before the canyon settles into its off-season pace. Add in aspens starting to turn gold against the canyon walls late in the month, and it’s not a bad time to bring a camera either.
If you’ve fished the South Platte all summer and want to see what it looks like without the crowds, this is the month to do it. Book a guided trip with North Fork Ranch Guide Service now and get on the water while the fish are still feeding hard, before the fall is over and the snow starts.