South Fork Boise River

May 19, 2026

By Barbless, compiled each morning from the gauges, forecasts and sources on this page.

South Fork Boise River

Current conditions for South Fork Boise River · Map, access and gauges

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Flow

500 cfs

Water Temp

54°F · Prime temp

Observed

126d ago

Hatch Status

BWOs, Baetis, some Caddis, and mixed bag of PMDs will be early season menu. Salmonflies on horizon.

Conditions

The South Fork opens Saturday, May 23, with cold early-season water at 54°F. Fish will be stacked and feeding subsurface before main hatches develop. Expect BWOs, Baetis, Caddis, and mixed PMDs early, with Salmonflies warming in faster than usual once temperatures rise.

Gauges

Techniques

  • Plan on spending most time nymphing early season. Worth throwing Chubby Chernobyl along shallower bank water and riffles with smaller, more imitative dropper underneath as searching approach.

Recommended flies

#16-20 Flashback Pheasant Tail#18 Olsen's Pheasant Tail#18-20 Silver Duracell#8-10 Knotty Hooker (Brown, Black, or Olive)#4 Godspeed Stone Brown#16-18 Red Neck#14-16 Yardley's Low Hole#16-18 Rosa Red Tag Jig#16-18 Rosa Orange#18-20 Burkus Baetis Cripple#16 Rusty Hackle Spinner#18-20 Last Chance Cripple BWO#18-20 Infrequent#10-12 Royal Chubby Chernobyl#8 Purple Chubby Chernobyl