Hatch Charts

The following represents major hatches as they occur in the area. Before streams clear, drop and warm sufficiently for hatches to appear consistently, anglers should fish nymphs and streamers. Early season hatches will appear at the warmest time of the day. As air and water temperatures rise during the season, hatches will occur earlier in the day. Late season angling (September/October) is often most productive with large nymphs and streamers as spawning fish become more territorial.



STONEFLIES

Salmon Fly -- (Pteronarcys californica)
Progressive hatch moving upstream several miles per day as water temperatures rise.

Madison River - Ennis to Hebgen Dam - June 25 to July 15

• Yellowstone River - July. 
• Gallatin River - June 15 to July 15.

Golden Stone -- (Hesperopela pacifica)

• Madison River - Jul.
• Yellowstone River - June 20 to July 20.
• Gallatin River - July.

Yellow Sally -- (Isoperia & Suwallia pallidula)

• Firehole River - June.
• Madison River - July 15 to August 15.
• Gallatin River - July 15 to August 15.

MAYFLIES

• Pale Morning Duns -- (Ephemerella inermis & infrequens). 
• Firehole River - June 1 to July 10.
• Madison River - (YNP) June 10 to July 15.
• Madison River - July 1 to August 15.
• Yellowstone River - July 5 to September 10.

Western Green Drake -- Ephemerella grandis)

• Madison River - (YNP) June 15 to July 10.

Brown Drake -- (Ephemera simulans)

• Gibbon River - June 25 to July 10.

Small Western Green Drake -- (Ephemerella flavilinea)

• Madison River - July 15 to August 10.
• Yellowstone River - July 20 to August 10.

Gray Drake -- (Siphlonurus occidentalis)

• Slough Creek - July 15 to September 15.
• Yellowstone River - July 15 to September 15.

Callibaetis -- (Callibaetis americanus)

• Hebgen Lake - July 15 to September 15.

Trico -- (Tricorythodes minutu)

• Hebgen Lake - July 10 to September 15.
• Madison River - August to September 30.

Blue Wing Olive -- (Baetis, many species)

• Firehole River - June, September, October.
• Madison River - September 1 to October 15.
• Yellowstone River - August 1 to October 30.

CADDIS - many species

• Firehole River - June 5 to July 15, September 10 to October 20.
• Madison River - June 25 to August 20.
• Gallatin River - July 1 to August 20.
• Yellowstone River - July 15 to August 30.

TERRESTRIALS
Hoppers, ants, beetles, crickets

• All streams July 5 to Sept 30.