Southwest Montana, Montana
Big Hole River Fishing Report: May 19, 2026
Big Hole River is in a useful fishing window today.
- Status
- good
- Flow trend
- falling
- Best window
- Late morning through afternoon
- Best methods
- nymphs, streamers, dry flies
Quick Summary
Big Hole River is in a useful fishing window today. USGS showed 2,480 cfs and 3.48 feet at 5:15 AM, with the flow trend falling. Water temperature was 45 F. Start with nymphs, then adjust to streamers or dry flies if fish begin feeding higher in the column. Wade conservatively and avoid pushy crossings; softer edges, bank access, or a boat are safer than mid-channel moves.
Conditions Snapshot
| Field | Value |
|---|---|
| Status | Good |
| Flow | 2,480 cfs at 5:15 AM |
| Gauge Height | 3.48 feet |
| Water Temp | 45 F |
| Clarity | Not reported |
| Trend | Falling |
| Best Window | Late morning through afternoon |
| Best Method | nymphs; streamers; dry flies |
| Wadeability | Limited |
Weather
For Melrose, MT, the National Weather Service forecast says: Today: A slight chance of rain after 2pm. Mostly sunny, with a high near 57. West northwest wind 2 to 7 mph. Chance of precipitation is 20%. Plan around wind, changing light, and any showers or storms rather than assuming a full-day dry fly window.
River Notes
The best starting point is water that matches the current gauge: inside seams, protected banks, riffle drop-offs, and slower buckets rather than the heaviest current. A falling trend is worth watching through the day; if the hydrograph turns sharply upward, clarity and wade safety can change before hatch timing does. Missing field values are left as Not reported rather than filled from guesswork.
Hatch Activity
Current hatch guidance is based on seasonal May patterns for this river system, current public report context where available, and today’s official gauge/weather check.
| Hatch | Size | Notes |
|---|---|---|
| March Brown | 10-12 | Look in softer seams when the river settles |
| Blue Winged Olive | 18-22 | Best during cloud cover |
| Caddis | 14-18 | Carry pupa and adults |
| Skwala/Stonefly | 8-12 | Useful as an attractor or nymph in faster banks |
Recommended Flies
| Category | Fly | Size | Notes |
|---|---|---|---|
| Dry | March Brown Cripple | 10-12 | Use over larger mayfly activity |
| Dry | Chubby Chernobyl | 8-12 | Prospecting bank water |
| Nymph | Pat’s Rubber Legs | 8-12 | Good anchor nymph |
| Nymph | Pheasant Tail | 14-18 | Trail behind stonefly |
| Streamer | Olive Sculpin | 4-8 | Low light or colored water |
Tactics
Start with nymphs in defined lanes and adjust weight, depth, or leader length before changing flies. If fish begin rising, simplify to a single dry or dry with an emerger/dropper and lengthen the leader. In bright or windy periods, return to subsurface presentations along protected banks and broken water. Re-check the gauge before wading new crossings, especially if the trend changes from stable or falling to rising.
Gauge Links
| Gauge | Flow | Temp | Link |
|---|---|---|---|
| Big Hole River near Melrose MT | 2,480 cfs | 45 F | USGS 06025500 |
Sources
Official sources checked: USGS station 06025500 and the National Weather Service forecast for the Melrose, MT area. This report is an original Custom FlyBox summary based on current official gauge and weather data, with local public conditions reports reviewed separately for hatch, access, and method context.