Bighorn River Flies & Hatch Chart by Month

Original close-up of a mayfly above the Bighorn River

HOW TO USE THE CHART

See what usually hatches, then look at the river.

Darker cells show the stronger usual activity. Lighter cells show months when you may also find that food. Actual timing changes with water temperature, weather and flow.

PossibleActivePeak

FoodJFMAMJJASONDSize

Midges3 of 33 of 33 of 33 of 32 of 32 of 32 of 31 of 32 of 32 of 33 of 33 of 3#18–24

Blue-winged olives1 of 31 of 32 of 33 of 33 of 32 of 31 of 31 of 32 of 33 of 33 of 31 of 3#16–22

PMDs0 of 30 of 30 of 30 of 31 of 33 of 33 of 32 of 31 of 30 of 30 of 30 of 3#16–20

Caddis0 of 30 of 30 of 31 of 31 of 32 of 33 of 33 of 32 of 31 of 30 of 30 of 3#14–18

Tricos0 of 30 of 30 of 30 of 30 of 31 of 32 of 33 of 33 of 31 of 30 of 30 of 3#20–24

Yellow Sallies0 of 30 of 30 of 30 of 31 of 32 of 33 of 31 of 30 of 30 of 30 of 30 of 3#14–18

Terrestrials0 of 30 of 30 of 30 of 30 of 31 of 32 of 33 of 32 of 31 of 30 of 30 of 3#8–18

Sowbugs and scuds3 of 33 of 33 of 33 of 33 of 33 of 33 of 33 of 33 of 33 of 33 of 33 of 3#14–20

Worms1 of 31 of 31 of 32 of 33 of 33 of 32 of 31 of 31 of 31 of 31 of 31 of 3#10–16

Leeches and baitfish2 of 32 of 32 of 33 of 33 of 33 of 32 of 32 of 33 of 33 of 33 of 32 of 3#4–12

BIGHORN RIVER FLIES

Patterns for every hatch.

Use the profiles below to choose a size and pattern, see when that food is usually available, and find a way to fish it.

#18–24

Midges

Window: Late morning in winter; variable through the day in warmer months

Approach: Fish larvae and pupae under an indicator. When you see fish rising steadily, try emergers or small adults.

Zebra midgeRed midgeSmokejumperCDC midge

#16–22

Blue-winged olives

Window: Late morning through afternoon, strongest during cloudy weather

Approach: Before the hatch, nymph where riffles deepen into runs. Switch to emergers or duns as fish begin taking them.

Juju BaetisCDC BaetisPheasant tailSparkle dun

#16–20

PMDs

Window: Morning through midday, sometimes later with cool or cloudy weather

Approach: Nymph before the hatch. Once fish are feeding near the surface, try emergers and duns.

Split-case PMDPMD nymphPale Morning DunPMD sparkle dun

#14–18

Caddis

Window: Morning activity and evening emergence; timing varies with temperature and wind

Approach: Try pupae and soft hackles during the hatch, then adults along banks and smooth water.

Black caddisTan caddisCDC caddisElk-hair caddis

#20–24

Tricos

Window: Early morning through late morning

Approach: Choose an individual rising fish and aim for a drag-free drift. Watch whether it is taking duns or spinners.

Trico spinnerTrico dunSmall parachuteBlack midge emerger

#14–18

Yellow Sallies

Window: Late morning through afternoon

Approach: Nymph riffles and the water just below them. Try adults near the banks when you see them on the water.

Yellow Sally nymphYellow StimulatorSmall stonefly nymph

#8–18

Terrestrials

Window: Late morning through afternoon, especially with wind

Approach: Fish close to grassy banks and along foam lines where insects collect.

Foam hopperAntBeetleSmall Chubby

#14–20

Sowbugs and scuds

Window: Year-round

Approach: These are dependable foods throughout the year. Try one as either the lead fly or the second fly in a nymph rig.

Ray CharlesSoft-hackle sowbugCarpet bugScud

#10–16

Worms

Window: Most useful during changing flow, higher water or reduced clarity

Approach: Use a visible worm as the lead fly, with a smaller natural pattern behind it.

San Juan wormWire wormMicro worm

#4–12

Leeches and baitfish

Window: Often useful in low light, under cloud cover or when the water is changing

Approach: Swing, strip or dead-drift these patterns along banks, through channels and into deeper, slower pockets.

Sparkle minnowSculpinWoolly buggerSmall leech

Bighorn River hatch chart.