Blue River Fly Fishing Report Below Dillon Dam | Summit County Winter Conditions

The Blue River below Dillon Dam is one of Colorado’s most technical tailwaters, and winter strips it down to pure fundamentals. Just outside Silverthorne, this stretch offers cold, ultra-clear water, consistent trout, and year-round access, but it demands precision. If you are looking for classic Summit County fly fishing where drift and depth matter more than fly choice, the Upper Blue delivers exactly that.

Updated: December 31, 2025

The Blue River below Dillon Dam is locked into a stable winter tailwater pattern. Steady bottom-release flows, ultra-clear water, and trout holding deep in slow, technical slots define the fishery right now. Feeding windows are short but reliable, centered around late morning through early afternoon when sunlight and water temperatures peak.

This week’s Blue River fly fishing report below Dillon Dam emphasizes discipline. Midges dominate the food supply, and trout are feeding selectively in deeper seams and winter troughs. Success comes from precise depth control, quiet approaches, and drag-free drifts. Rush presentations or fish above the zone, and the river will let you know immediately.

Listen to the Audio Overview

Conditions Summary

• Flow: 107 CFS
• Temps: Water Temp: No Data | Air Temp: 6.1°F
• Wind: 4.1 mph
• Clarity: Ultra clear
• Crowds: Medium
• Best Times: Late morning through early afternoon
• Confidence: 80%
• Fishing Type Focus: Nymphing with small flies and precise depth control
• River Rating: Condition ⭐️
• Scores: Dry Fly ⭐️ | Nymph ⭐️⭐️⭐️⭐️⭐️ | Streamer ⭐️⭐️⭐️

Weather

Expect classic high-elevation winter conditions. Cold mornings dominate, with brief midday warming when the sun clears the valley walls. Calm, sunny days fish best. Wind or heavy cloud cover shortens already narrow feeding windows.

Top Flies in Your Box This Week

• Black Beauty 20 to 24
• Zebra Midge (black or red) 20 to 22
• Mercury Midge 20 to 22
• Top Secret Midge 22 to 24
• RS2 (black or gray) 20 to 22
• WD-40 20 to 22
• Small Pheasant Tail 18 to 20
• Juju Baetis 20 to 22

Pro Rig of the Week: Dillon Dam Tiny Water Column Rig

• Indicator: Very small yarn or low-profile air-lock
• Lead Fly: Small Pheasant Tail 18 to 20 or RS2 20
• Dropper: Black Beauty or Top Secret Midge 22 to 24
• Weight: One micro to small split shot adjusted carefully
• Target Water: Floodwall seams, deep winter troughs, and slow inside edges

Hatch Chart for December

Download the Blue River Hatch Chart

Access Points

Silverthorne Town Stretch ⭐⭐⭐⭐⭐
Classic floodwall water with consistent winter trout holding lanes.
Rating: Five gold stars

Blue River Trail Pullouts ⭐⭐⭐⭐☆
Long glides and deep seams with slightly less pressure.
Rating: Four gold stars

Lower Corridor Access ⭐⭐⭐⭐☆
Broader winter lanes and productive seams when flows are steady.
Rating: Four gold stars

Stop Here After the River

Angry James Brewing Co. (Silverthorne)
A relaxed post-river hangout with warm food-truck meals, mountain-town energy, and reliably good beer.
What to order: The Resolute IPA with a rotating hot entrée from the food truck lineup.

Local Regulations and Notes

• Tailwater flows change; always check the release before fishing
• Extremely clear water requires long leaders and 6X tippet
• Sight-fishing is possible but demands quiet wading
• Respect town pathways and private property along the corridor

FAQ

Is the Blue River Below Dillon Dam Good for Fly Fishing Right Now?

Yes, but only if you fish it like a winter tailwater. The Blue River below Dillon Dam offers consistent trout presence year-round, but winter success depends on fishing midday, using small midge patterns, and maintaining precise depth control. Feeding windows are short but reliable when light and temperatures peak.

How Technical Is Fly Fishing the Blue River Below Dillon Dam?

Very. Ultra-clear water, steady tailwater flows, and heavy angling pressure make this one of the most technical winter fisheries in Summit County. Trout feed selectively and punish poor drifts immediately. This stretch rewards anglers who slow down and fish deliberately.

Q: Is the Blue River below Dillon Dam good in winter?
A: Yes. Cold but consistent flows make it one of Colorado’s most predictable winter tailwaters.

Q: What weight rod should I bring?
A: A 4 or 5 weight with a long leader setup is ideal for this technical water.

Q: Are dries an option?
A: Rarely, but on the warmest calm afternoons you might find isolated midge clusters.

Q: What is the biggest mistake anglers make here?
A: Heavy footsteps and heavy rigs. Everything here requires subtlety.

Q: Does the flow matter more on a tailwater?
A: Yes. Even small changes from the dam can shift where trout stack.

Q: When is the best time of day?
A: Midday, when water temps rise the most.

Q: Is the Blue River good in winter?
A: Yes. It is one of the most consistent winter tailwaters in Colorado, but it is very technical.

Q: What is the biggest mistake anglers make here?
A: Fishing too heavy or too fast. Subtle depth control matters more than fly changes.

Q: Are dry flies an option right now?
A: Rarely. Subsurface midge patterns dominate winter success.

Q: What leader and tippet setup works best?
A: Long leaders with 5X to the lead fly and 6X to the midge dropper.

Q: Does wind ruin the fishing?
A: It can. Wind makes precise drifts extremely difficult on this stretch.

Q: When does the bite shut down?
A: Typically mid-afternoon once shadows and colder air settle into the corridor.

Companion Article

Colorado Winter Trout Feeding Behavior in Clear Tailwaters