California Fly Fishing Hatch Chart
Interactive fly fishing hatch chart for California. See which mayflies, caddisflies, stoneflies, and midges are hatching each month and get fly pattern recommendations. Based on 10 years of scientific observation data (2015–2024).
Using the California hatch chart
This statewide chart compares when aquatic insect observations have been recorded in California. Select a month to compare the share of annual mayfly, caddisfly, stonefly, and midge observations, then review fly patterns commonly used to imitate those insect groups.
Our California hatch chart is built from 10 years of scientific observation data (2015–2024), covering the major aquatic insect orders: Ephemeroptera (mayflies), Trichoptera (caddisflies), Plecoptera (stoneflies), and Diptera (midges). Use it to plan your fishing trips around the most productive emergence windows of the season. Actual timing varies with elevation, latitude, water temperature, and seasonal weather, so confirm current activity with local reports and on-water observation.
California river guides
- Truckee River — The Truckee River is a high-elevation California and Nevada trout river where snowmelt, reservoir releases, and changing canyon conditions make current flow data essential.
- McCloud River — The McCloud River is a cold northern California trout river with spring influence and well-defined mapped reaches. Its gauge search is a useful first check when planning a wade.
- Sacramento River — The Sacramento River is a large northern California river system with extensive mapped water and a broad range of trout, steelhead, and salmon habitat.
- Kern River — The Kern River is a high-gradient California river system with mapped trout reaches and large changes in character between its upper and lower sections.