What hatches in Colorado in November?

Midges and blue-winged olives on tailwaters, with egg patterns working during the brown trout spawn.

Front Range Hatch Chart: Colorado Bugs by Month

Updated November 14, 2026. 2 min read.

Bug	Peak months	Sizes	Where
Midges	All year; Nov–Mar are prime	#20–26	Every tailwater
Blue-winged olives (Baetis)	Mar–May, Sep–Nov	#18–22	Platte, Blue, Big T, Pan
Mysis shrimp	All year	#16–18	Blue (Dillon), Fryingpan (Ruedi)
Eggs / spawn	Mar–May (rainbows), Oct–Nov (browns)	#14–18	Dream Stream, Deckers, 11-Mile
Caddis	May–Aug	#14–18	Platte, Big T, freestones
PMDs	Jun–Aug	#16–18	Platte, Pan, Blue
Tricos	Jul–Sep	#20–24	Deckers, Cheesman
Green drakes	Jul–Sep	#10–12	Fryingpan
Stoneflies	May–Jul	#6–10	Freestones
Hoppers	Jul–Sep	#8–14	Meadows, Dream Stream, Big T

Hatches shift with weather, elevation and dam releases. Use this chart to stock your box, then check a local shop report for the week.

Look for rising fish and bugs on the surface or in the air, and check spiderwebs and streamside rocks for shucks.
Fish swirling without breaking the surface are usually eating emergers just under the film.
When in doubt, match the size first, then the color, then the shape.

Hatches run later at higher elevations. A hatch that's on in the foothills in May may hit a high meadow stream in late June.

What hatches in Colorado in November?: Midges and blue-winged olives on tailwaters, with egg patterns working during the brown trout spawn.