Fly Fishing Hatch Chart by Month and Water Type

What is typically hatching, and which fly patterns match it. Generated from the curated chart inside the Hatch Window app: 24 hatch entries covering Mountain West, Northeast (Catskills/Appalachians), Midwest (Driftless/Great Lakes), South (Southern Appalachians/Southeast tailwaters).

Pick a month

Month	Typically active
January	Midges, Scuds & Sowbugs
February	Midges, Blue-Winged Olive, Skwala Stonefly, Scuds & Sowbugs, Quill Gordon
March	Midges, Blue-Winged Olive, Skwala Stonefly, Baitfish / sculpins (streamer season), Scuds & Sowbugs, Quill Gordon, Blue Quill
April	Midges, Blue-Winged Olive, Skwala Stonefly, Caddisflies (general), Baitfish / sculpins (streamer season), Hendrickson, Grannom Caddis, Scuds & Sowbugs, Quill Gordon, Blue Quill
May	Midges, Caddisflies (general), Salmonfly / Golden Stonefly, Hendrickson, Sulphur, March Brown, Grannom Caddis, Green Drake (Eastern) / Coffin Fly, Scuds & Sowbugs, Yellow Sally (Little Yellow Stonefly), Light Cahill
June	Midges, Caddisflies (general), Salmonfly / Golden Stonefly, Pale Morning Dun, Green Drake (Western), Sulphur, March Brown, Isonychia / Slate Drake, Green Drake (Eastern) / Coffin Fly, Hex (Giant Michigan Mayfly), Scuds & Sowbugs, Yellow Sally (Little Yellow Stonefly), Light Cahill
July	Midges, Caddisflies (general), Salmonfly / Golden Stonefly, Pale Morning Dun, Green Drake (Western), Trico, Hoppers, ants & beetles, Isonychia / Slate Drake, Hex (Giant Michigan Mayfly), Scuds & Sowbugs, Yellow Sally (Little Yellow Stonefly), Light Cahill
August	Midges, Caddisflies (general), Pale Morning Dun, Trico, Hoppers, ants & beetles, Isonychia / Slate Drake, Scuds & Sowbugs, White Fly
September	Midges, Blue-Winged Olive, Trico, Hoppers, ants & beetles, Sulphur, Isonychia / Slate Drake, Scuds & Sowbugs, White Fly, Mahogany Dun
October	Midges, Blue-Winged Olive, Baitfish / sculpins (streamer season), Scuds & Sowbugs, Mahogany Dun
November	Midges, Blue-Winged Olive, Baitfish / sculpins (streamer season), Scuds & Sowbugs
December	Midges, Scuds & Sowbugs

Month

Typically active

January

Midges, Scuds & Sowbugs

February

Midges, Blue-Winged Olive, Skwala Stonefly, Scuds & Sowbugs, Quill Gordon

March

Midges, Blue-Winged Olive, Skwala Stonefly, Baitfish / sculpins (streamer season), Scuds & Sowbugs, Quill Gordon, Blue Quill

April

Midges, Blue-Winged Olive, Skwala Stonefly, Caddisflies (general), Baitfish / sculpins (streamer season), Hendrickson, Grannom Caddis, Scuds & Sowbugs, Quill Gordon, Blue Quill

May

Midges, Caddisflies (general), Salmonfly / Golden Stonefly, Hendrickson, Sulphur, March Brown, Grannom Caddis, Green Drake (Eastern) / Coffin Fly, Scuds & Sowbugs, Yellow Sally (Little Yellow Stonefly), Light Cahill

June

Midges, Caddisflies (general), Salmonfly / Golden Stonefly, Pale Morning Dun, Green Drake (Western), Sulphur, March Brown, Isonychia / Slate Drake, Green Drake (Eastern) / Coffin Fly, Hex (Giant Michigan Mayfly), Scuds & Sowbugs, Yellow Sally (Little Yellow Stonefly), Light Cahill

July

Midges, Caddisflies (general), Salmonfly / Golden Stonefly, Pale Morning Dun, Green Drake (Western), Trico, Hoppers, ants & beetles, Isonychia / Slate Drake, Hex (Giant Michigan Mayfly), Scuds & Sowbugs, Yellow Sally (Little Yellow Stonefly), Light Cahill

August

Midges, Caddisflies (general), Pale Morning Dun, Trico, Hoppers, ants & beetles, Isonychia / Slate Drake, Scuds & Sowbugs, White Fly

September

Midges, Blue-Winged Olive, Trico, Hoppers, ants & beetles, Sulphur, Isonychia / Slate Drake, Scuds & Sowbugs, White Fly, Mahogany Dun

October

Midges, Blue-Winged Olive, Baitfish / sculpins (streamer season), Scuds & Sowbugs, Mahogany Dun

November

Midges, Blue-Winged Olive, Baitfish / sculpins (streamer season), Scuds & Sowbugs

December

Midges, Scuds & Sowbugs

By water type

The chart tags each entry with the water types where it is commonly fished: tailwater, freestone or spring creek.

Tailwater

Month	Hatches
January	Midges, Scuds & Sowbugs
February	Midges, Blue-Winged Olive, Scuds & Sowbugs
March	Midges, Blue-Winged Olive, Baitfish / sculpins (streamer season), Scuds & Sowbugs
April	Midges, Blue-Winged Olive, Caddisflies (general), Baitfish / sculpins (streamer season), Scuds & Sowbugs
May	Midges, Caddisflies (general), Sulphur, Scuds & Sowbugs, Yellow Sally (Little Yellow Stonefly)
June	Midges, Caddisflies (general), Pale Morning Dun, Sulphur, Scuds & Sowbugs, Yellow Sally (Little Yellow Stonefly)
July	Midges, Caddisflies (general), Pale Morning Dun, Trico, Hoppers, ants & beetles, Scuds & Sowbugs, Yellow Sally (Little Yellow Stonefly)
August	Midges, Caddisflies (general), Pale Morning Dun, Trico, Hoppers, ants & beetles, Scuds & Sowbugs, White Fly
September	Midges, Blue-Winged Olive, Trico, Hoppers, ants & beetles, Sulphur, Scuds & Sowbugs, White Fly, Mahogany Dun
October	Midges, Blue-Winged Olive, Baitfish / sculpins (streamer season), Scuds & Sowbugs, Mahogany Dun
November	Midges, Blue-Winged Olive, Baitfish / sculpins (streamer season), Scuds & Sowbugs
December	Midges, Scuds & Sowbugs

Month

Hatches

January

Midges, Scuds & Sowbugs

February

Midges, Blue-Winged Olive, Scuds & Sowbugs

March

Midges, Blue-Winged Olive, Baitfish / sculpins (streamer season), Scuds & Sowbugs

April

Midges, Blue-Winged Olive, Caddisflies (general), Baitfish / sculpins (streamer season), Scuds & Sowbugs

May

Midges, Caddisflies (general), Sulphur, Scuds & Sowbugs, Yellow Sally (Little Yellow Stonefly)

June

Midges, Caddisflies (general), Pale Morning Dun, Sulphur, Scuds & Sowbugs, Yellow Sally (Little Yellow Stonefly)

July

Midges, Caddisflies (general), Pale Morning Dun, Trico, Hoppers, ants & beetles, Scuds & Sowbugs, Yellow Sally (Little Yellow Stonefly)

August

Midges, Caddisflies (general), Pale Morning Dun, Trico, Hoppers, ants & beetles, Scuds & Sowbugs, White Fly

September

Midges, Blue-Winged Olive, Trico, Hoppers, ants & beetles, Sulphur, Scuds & Sowbugs, White Fly, Mahogany Dun

October

Midges, Blue-Winged Olive, Baitfish / sculpins (streamer season), Scuds & Sowbugs, Mahogany Dun

November

Midges, Blue-Winged Olive, Baitfish / sculpins (streamer season), Scuds & Sowbugs

December

Midges, Scuds & Sowbugs

Freestone

Month	Hatches
January	Midges
February	Midges, Blue-Winged Olive, Skwala Stonefly, Quill Gordon
March	Midges, Blue-Winged Olive, Skwala Stonefly, Baitfish / sculpins (streamer season), Quill Gordon, Blue Quill
April	Midges, Blue-Winged Olive, Skwala Stonefly, Caddisflies (general), Baitfish / sculpins (streamer season), Hendrickson, Grannom Caddis, Quill Gordon, Blue Quill
May	Midges, Caddisflies (general), Salmonfly / Golden Stonefly, Hendrickson, Sulphur, March Brown, Grannom Caddis, Green Drake (Eastern) / Coffin Fly, Yellow Sally (Little Yellow Stonefly), Light Cahill
June	Midges, Caddisflies (general), Salmonfly / Golden Stonefly, Pale Morning Dun, Green Drake (Western), Sulphur, March Brown, Isonychia / Slate Drake, Green Drake (Eastern) / Coffin Fly, Hex (Giant Michigan Mayfly), Yellow Sally (Little Yellow Stonefly), Light Cahill
July	Midges, Caddisflies (general), Salmonfly / Golden Stonefly, Pale Morning Dun, Green Drake (Western), Hoppers, ants & beetles, Isonychia / Slate Drake, Hex (Giant Michigan Mayfly), Yellow Sally (Little Yellow Stonefly), Light Cahill
August	Midges, Caddisflies (general), Pale Morning Dun, Hoppers, ants & beetles, Isonychia / Slate Drake, White Fly
September	Midges, Blue-Winged Olive, Hoppers, ants & beetles, Sulphur, Isonychia / Slate Drake, White Fly, Mahogany Dun
October	Midges, Blue-Winged Olive, Baitfish / sculpins (streamer season), Mahogany Dun
November	Midges, Blue-Winged Olive, Baitfish / sculpins (streamer season)
December	Midges

Month

Hatches

January

Midges

February

Midges, Blue-Winged Olive, Skwala Stonefly, Quill Gordon

March

Midges, Blue-Winged Olive, Skwala Stonefly, Baitfish / sculpins (streamer season), Quill Gordon, Blue Quill

April

Midges, Blue-Winged Olive, Skwala Stonefly, Caddisflies (general), Baitfish / sculpins (streamer season), Hendrickson, Grannom Caddis, Quill Gordon, Blue Quill

May

Midges, Caddisflies (general), Salmonfly / Golden Stonefly, Hendrickson, Sulphur, March Brown, Grannom Caddis, Green Drake (Eastern) / Coffin Fly, Yellow Sally (Little Yellow Stonefly), Light Cahill

June

Midges, Caddisflies (general), Salmonfly / Golden Stonefly, Pale Morning Dun, Green Drake (Western), Sulphur, March Brown, Isonychia / Slate Drake, Green Drake (Eastern) / Coffin Fly, Hex (Giant Michigan Mayfly), Yellow Sally (Little Yellow Stonefly), Light Cahill

July

Midges, Caddisflies (general), Salmonfly / Golden Stonefly, Pale Morning Dun, Green Drake (Western), Hoppers, ants & beetles, Isonychia / Slate Drake, Hex (Giant Michigan Mayfly), Yellow Sally (Little Yellow Stonefly), Light Cahill

August

Midges, Caddisflies (general), Pale Morning Dun, Hoppers, ants & beetles, Isonychia / Slate Drake, White Fly

September

Midges, Blue-Winged Olive, Hoppers, ants & beetles, Sulphur, Isonychia / Slate Drake, White Fly, Mahogany Dun

October

Midges, Blue-Winged Olive, Baitfish / sculpins (streamer season), Mahogany Dun

November

Midges, Blue-Winged Olive, Baitfish / sculpins (streamer season)

December

Midges

Spring creek

Month	Hatches
January	Midges, Scuds & Sowbugs
February	Midges, Blue-Winged Olive, Scuds & Sowbugs
March	Midges, Blue-Winged Olive, Baitfish / sculpins (streamer season), Scuds & Sowbugs, Blue Quill
April	Midges, Blue-Winged Olive, Caddisflies (general), Baitfish / sculpins (streamer season), Hendrickson, Grannom Caddis, Scuds & Sowbugs, Blue Quill
May	Midges, Caddisflies (general), Hendrickson, Sulphur, Grannom Caddis, Scuds & Sowbugs, Light Cahill
June	Midges, Caddisflies (general), Sulphur, Hex (Giant Michigan Mayfly), Scuds & Sowbugs, Light Cahill
July	Midges, Caddisflies (general), Trico, Hoppers, ants & beetles, Hex (Giant Michigan Mayfly), Scuds & Sowbugs, Light Cahill
August	Midges, Caddisflies (general), Trico, Hoppers, ants & beetles, Scuds & Sowbugs
September	Midges, Blue-Winged Olive, Trico, Hoppers, ants & beetles, Sulphur, Scuds & Sowbugs
October	Midges, Blue-Winged Olive, Baitfish / sculpins (streamer season), Scuds & Sowbugs
November	Midges, Blue-Winged Olive, Baitfish / sculpins (streamer season), Scuds & Sowbugs
December	Midges, Scuds & Sowbugs

Month

Hatches

January

Midges, Scuds & Sowbugs

February

Midges, Blue-Winged Olive, Scuds & Sowbugs

March

Midges, Blue-Winged Olive, Baitfish / sculpins (streamer season), Scuds & Sowbugs, Blue Quill

April

Midges, Blue-Winged Olive, Caddisflies (general), Baitfish / sculpins (streamer season), Hendrickson, Grannom Caddis, Scuds & Sowbugs, Blue Quill

May

Midges, Caddisflies (general), Hendrickson, Sulphur, Grannom Caddis, Scuds & Sowbugs, Light Cahill

June

Midges, Caddisflies (general), Sulphur, Hex (Giant Michigan Mayfly), Scuds & Sowbugs, Light Cahill

July

Midges, Caddisflies (general), Trico, Hoppers, ants & beetles, Hex (Giant Michigan Mayfly), Scuds & Sowbugs, Light Cahill

August

Midges, Caddisflies (general), Trico, Hoppers, ants & beetles, Scuds & Sowbugs

September

Midges, Blue-Winged Olive, Trico, Hoppers, ants & beetles, Sulphur, Scuds & Sowbugs

October

Midges, Blue-Winged Olive, Baitfish / sculpins (streamer season), Scuds & Sowbugs

November

Midges, Blue-Winged Olive, Baitfish / sculpins (streamer season), Scuds & Sowbugs

December

Midges, Scuds & Sowbugs

Starter rivers

Hatch Window ships a starter list of well-known Western waters, each with a USGS gauge. Each page shows the gauge number, a link to the official USGS page, and the chart entries for that water type in the Mountain West.

Check local regulations. Seasons, gear rules, closures and access vary by water and change often. Check current regulations and conditions for the water you plan to fish, and carry a valid license.

About this page. Hatch timing varies by year, elevation and water temperature. Months here are typical ranges from the Hatch Window curated chart, a starting point and not a live report of what is hatching today. Hatch Window is a free fly-fishing companion app from Baker Ventures LLC with a built-in version of this chart, plus streamflow from USGS and weather from Open-Meteo. Data source: Hatch Window source files src/data/hatches.ts and src/data/spots.ts, commit c45001f.