Pennsylvania Fly Fishing Hatch Chart

Interactive fly fishing hatch chart for Pennsylvania. 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 Pennsylvania hatch chart

This statewide chart compares when aquatic insect observations have been recorded in Pennsylvania. 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 Pennsylvania 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.

Pennsylvania river guides

• Allegheny River — The Allegheny is a large Pennsylvania river with extensive mapped trout and fishing-water coverage. Its size makes gauge location, access, and flow trend essential parts of trip planning.
• Penns Creek — Penns Creek is a limestone-influenced Pennsylvania trout stream with a strong hatch-fishing identity and enough flow variation that a current gauge check is worthwhile.

Check current Pennsylvania river flows and gauge conditions.