Lower Big Hole — Hatch Chart
Big Hole · Divide / Melrose area to Twin Bridges (confluence with Beaverhead)
Mayfly
Stonefly
Caddis
Midge
Terrestrial
| darker = peak activity
Insect
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Size
Mayflies
BWOs (Spring)
Mar–May
· #14-16
BWOs (Fall)
Sep–Oct
· #16-22
PMDs
Jun–Jul
· #14-16
· 58°F
Tricos
Jul–Sep
· #18-22
Stoneflies
Skwalas
Mar–Apr
· #6-10
Salmonflies
Jun–Jun
· #4-8
· 56°F
Golden Stones
Jun–Jul
· #8-12
Yellow Sallies
Jun–Aug
· #8-16
Midges
Midges
Jan–Dec
· #18-26