Blue River
14 Day Forecast: Look for sporadic hatches of midges and some sporadic mayflies and caddis.
Effective Patterns: #20-22 Top Secret Midge, #20-22 Manhattan Midge, #20-22 Jujubaetis, #20-22 Top Secret Baetis, #20-24 Chocolate Foam Wing Emerger, #18 Micro San Juan Worm, #20-22 Red Larva, #20 Mercurry Blood Midge, #20 Flashback Mercury Black Beauty, #18 Graphic Caddis, #18 Buckskin, #10 Amy's Ant, #16 PMD, #12 Green Drake, #14-16 Elk Hair Caddis, #22 Mole Fly, and #16-20 Parachute Adams.
Measurements
Get Information for Fly Fishing on the Blue River Near Frisco, CO by Pat Dorsey
Many anglers I know have a love-hate relationship with the Blue River. Just about the time you think you have the river figured out, a humbling experience devastates your ego. The Blue River is a fantastic fishery and a favorite of mine. The Blue certainly is a beautiful as they come, and gives visiting anglers a real sense of Colorado. It’s a tough river at times, but a good challenge will always make you a better fly-fisherman. The water is extremely cold coming off the bottom of Lake Dillon. This cold water dictates and controls the feeding window of the trout. It’s not a great morning fishery, but as the water gradually warms up throughout the day, the fishing improves dramatically. The upper stretches of the Blue (from the base of the dam through Silverthorne) holds trophy trout, fattening up on Mysis Shrimp from the lake above. The water is gin clear requiring perfect presentations. Down stream the river changes back in a typical mountain trout stream with a diverse insect life. Several tributaries inter the river before it spills into Green Mountain Reservoir.
The river is lined with cottonwood trees and willows and is tucked to the east of the beautiful Gore Range. Because the water is so cold the river fishes best from mid-day to dark. Anglers can expect to catch mostly brown trout, a hand full of cut-bows as well as a few rainbows and the river can be excellent with dry fly patterns later in the afternoons and evenings. The hatches include blue wing olives, caddis, red quills, green drakes, pmd’s, and stoneflies. The regulations are catch and release in Silverthorne and on the lower reaches the limit is two trout over 16 inches in length and is artificial flies and lures only.
Tips & Other Information:
Nothing new to report…outflows below Dillon Reservoir are still at 56 cfs. Dillon Reservoir is at 78% capacity as of this morning so look for low outflows for the remainder of the summer season. Fishing is technical with the low water so you’ll need to bring your A-game. Plan on reliable hatches of midges in the morning followed by some caddis and sporadic mayfly activity. The feeders creeks are adding some water but not much to speak of. Keep and eye on water temperatures and quit fishing if they hit 67 degrees. Be mindful of our finned friends and keep them wet and release them quickly. Revised 7/23/26.