Free Resource · Updated 2026
The Blue River flows from Green Mountain Reservoir through Silverthorne before joining the Colorado. It is a tailwater with cold, clear water and a steady population of wild brown trout. Midges and Blue-Winged Olives are the primary hatches, with Caddis adding action in summer.
Blue River Hatch Calendar — Quick Reference
There are two main sections to consider on the Blue. The stretch just below Green Mountain Reservoir is wild and remote with fewer anglers. The section through Silverthorne and into the canyon below town is more accessible and sees more pressure but also holds a lot of fish.
The Blue is a midge river first and foremost. It runs cold all year and the trout feed heavily on midges in every life stage. Winter fishing is productive for anglers willing to handle the cold, and midges bring fish to the surface on mild afternoons even in January and February.
Summer sees Caddis and some Stonefly activity that diversifies the fishing. The canyon section below Silverthorne fishes well on summer evenings when Caddis are hatching. Fall BWOs are consistent and the brown trout become more aggressive as spawn approaches.
See the full Colorado Fly Hatch Chart for hatch timing across all of Colorado's top trout streams.
Check Conditions Near Blue RiverWhat to Fish
Midges are always happening on the Blue River. The tailwater keeps temperatures stable and the midge populations dense. Winter fishing below Green Mountain Dam can be surprisingly productive on calm days. Fish cluster midges just under the surface film and adults on top when the weather cooperates.
Recommended: Zebra Midge, Griffith's Gnat #22-26
Fall BWO hatches on the Blue River are reliable and bring the larger brown trout to the surface. The canyon section below Silverthorne sees good BWO activity on overcast October days. A size 20 RS2 or Parachute BWO fished on a dead drift will bring up fish that are impossible to spot otherwise.
Recommended: Parachute Adams, RS2 #18-22
Caddis evenings on the Blue River are the best dry fly action of the summer. Fish the canyon section below Silverthorne from early evening through dark. A size 16 Elk Hair Caddis covers most situations. When fish are rising but ignoring your dry, try a soft hackle just under the surface.
Recommended: Elk Hair Caddis #14-18
Golden Stoneflies hatch in late May and June on the Blue. The adults crawl up on rocks along the bank and fish watch for them falling or skating on the surface. Fish a large Stimulator tight to the bank with some movement. The hatch is short but can trigger some of the best fishing of the season.
Recommended: Golden Stone, Stimulator #8-10
FlyFishFinder combines hatch knowledge with live gauge alerts, Prime condition indicators, and real angler intel so you show up on the right day, not the wrong one.
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