Lamar River Fly Fishing Report - December 12/3/2025
LAMAR RIVER FLY FISHING REPORT
Yellowstone National Park — Lamar Valley
Current River Conditions
Status: Closed to fishing (seasonal closure, typical through late spring)
Park Rule: Follow posted closures and consult Yellowstone National Park for exact opening dates (season usually re-opens on the Saturday of Memorial Day weekend).
Water Temp: Near freezing to low 30s °F (0–3°C) in December
Surface: Cold, low insect activity; occasional open water pockets depending on weather
Weather: Winter conditions — snow, cold nights; expect limited access and icy trailheads.
Flows: Typical base flows for winter (variable) — watch for sudden changes from upstream releases or heavy rain/snowmelt events.
Clarity: Usually clear; cold clear water increases trout wariness.
Roads: Sections may be snow-covered. Vehicle chains & winter gear recommended.
Wildlife: Lamar Valley is prime winter range for wolves, bison, elk and still-used by bears—stay alert and carry required safety gear.
Permits: No fishing permitted while river is closed—violations enforced.
What This Means Practically
Because the river is closed, the actionable guidance here is planning and preparation. Use this downtime to refine winter tactics for year-round waters nearby, tune your rigs, and restock patterns that work in cold-water conditions. If you must get on water outside Yellowstone, aim for rivers and stretches that remain open year-round (for example, the Madison and Gardiner sections where allowed) and always verify local regulations.
Winter Insect & Fish Activity (December)
| Insect / Food | Activity | Notes for Anglers |
|---|---|---|
| Midges | Low–Moderate | Midges are the primary winter food — fish often key on subsurface pupae and emerger drift on warmer afternoons. |
| Larvae / Worms / Eggs | Occasional | Gravel runs and deep pools hold worms and egg pockets; subtle, slow presentations win. |
| Streamers / Baitfish | Opportunistic | Large trout (when present and active) will take slow-stripped streamers in deep runs and near structure. |
Recommended Flies (Winter & Year‑Round Alternatives)
Below are winter-focused patterns that match the flies in the supplied fly sheet. If you fish open, year‑round sections (Gardiner, Madison, private waters), these are excellent choices. Each pattern links to the exact fly entry in your fly inventory.
| Pattern | Use | Source Link |
|---|---|---|
| Black Zebra Midge (small, beadhead) | Midge pupa/emerger — indicator or euro nymphing (sizes #18–22) | Black Zebra Midge |
| Redneck Midge | Winter midge imitations for the dropper or point fly | Redneck Midge |
| Tungsten Split Case Nymph - BWO / PMD variants | High-density nymph for euro/indicator rigs — great for deep winter pockets | Split Case - BWO • Split Case - PMD |
| Pheasant Tail Tungsten | Go-to classic nymph — versatile as a point fly under an indicator or in euro rigs | Pheasant Tail Tungsten |
| Tungsten Pat's Rubber Legs | Heavy stonefly / attractor nymph — fish deep seams and runs when trout hold low | Tungsten Pat's Rubber Legs |
| Cheech Leech (Black / Black-Red) | Streamer for slow, deep retrieves — trigger for lethargic winter trout | Cheech Leech - Black • Black/Red |
| Sculpzilla (Natural / Olive) | Sculpin/baitfish imitation — slow strips across deep heads and tailouts | Sculpzilla - Natural • Sculpzilla - Olive |
| Sunny Side Up (Egg patterns) | Eggs and attractor—use in gravel run-outs and spawning pockets where legal | Sunny Side Up - Sunburst |
| Egan's Warrior Perdigon / Rainbow Warrior Perdigon | Fast-sinking, slim nymph for precise euro presentations in winter runs | Egan's Warrior Perdigon |
Tactics & Winter Tips
- Slow everything down. Fish metabolic rates are low — long, slow drifts or slow, short-stripped streamers win.
- Fish deeper. Target deep tails, seam lines, and undercut banks; add tungsten or heavier beadheads.
- Euro / Tight-line nymphing. Keeps flies in the feeding zone; use slim, tungsten patterns on the point.
- Indicators. Use long, subtle leaders and small strike indicators; watch for soft takes.
- Leader & tippet. Use fluorocarbon for abrasion resistance and stealth; 6–8 ft leaders with 4–6X tippet for midges.
- Streamer approach. Slow strips with pauses; short pulls mimic an injured baitfish in cold water.
- Stealth & patience. Clear water + low light = spooky fish. Make long, accurate casts and keep profile low.
Regulations, Conservation & Safety
Do not fish closed waters — Yellowstone enforces seasonal closures to protect trout during vulnerable periods. When fishing open waters nearby, practice gentle handling, use barbless hooks where required, and follow local bag and size limits. In winter terrain, travel with proper clothing, let someone know your plan, and respect wildlife—give animals plenty of space and follow park guidance.
Planning for Next Season
Use the winter months to prepare: restock midges, slim nymphs, and a couple of heavy streamers. Tune leaders for euro and indicator rigs, sharpen hooks, and map put-in points for the Lamar’s re-opening (usually the Saturday of Memorial Day weekend). Keep an eye on park announcements for the official opening date and any fish-protection adjustments.
