This is a general Pennsylvania hatch chart for the most common aquatic and terrestrial insects inhabiting Pennsylvania streams and rivers. It provides hatch dates, emergence times, recommended fly sizes and patterns. The most common hatches you’ll find when fly fishing include Caddis, Blue Quill, Hendrickson, March Brown, Sulfur and Cahills. Not all hatches occur on all streams.
The chart below covers general fly hatches for the state of Pennsylvania including Penns Creek, Big Fishing Creek, Manatawny Creek, Spring Creek, Tulpehocken Creek, Bald Eagle, Pine Creek, Cedar Run, Lehigh River, Pohopoco, Slate Run, Mud Run, Bushkill Creek, Broadhead Creek, Young Women’s Creek, Little Juniata, Kettle Creek, Lackawanna River, Lackawaxen River, Class A Trout Streams. Dates are approximates. Emergence time can start earlier or be delayed by cooler or warmer temperatures.
| Fly Hatch | Size | Dates | Emergence Time |
|---|---|---|---|
| Midges | January-December | ||
| Little Black Stonefly | 16 | February-Mid April | Morning and afternoon |
| Little Blue Winged Olive (BWO) | 16–20 | March-Mid July | Late morning and early afternoon |
| Little Black Caddis | 18 | March-May | Late morning |
| Dark Quill Gordon | 14 | April-Mid May | Afternoon |
| Quill Gordon | 14 | April-Mid May | Early afternoon |
| Blue Quill | 16–18 | April-Mid May | Early afternoon |
| Red Quill | 14–16 | April-Early May | Early Afternoon to Early Evening |
| Grannoms Caddis | 12–14 | April-Mid May | Mid Morning to Late Afternoon |
| Caddis - Olive, Tan, Black | 12–20 | April-September | Late Morning to Evening |
| Hendrickson | 12–14 | April-Early May | Late afternoon to early evening |
| Black Quill | 14 | April-May | Morning and afternoon |
| Great Speckled Olive Dun | 14 | April-May | Early afternoon |
| Little Blue Dun | 20 | April-May | Afternoon and evening |
| Green Caddis | 14 | April-August | Morning and afternoon |
| Golden Stonefly | 12 | May-June | Early Afternoon to Early Evening |
| Early Dark Stonefly | 18–20 | April-August | Mid Morning to Late Afternoon |
| Big Sulfur | 14–16 | May-June | Evenings |
| March Brown | 10–12 | May-Mid July | Afternoon to Evening |
| Sulphur | 12–16 | May-July | |
| Tan Caddis | 14–16 | April-October | |
| Green Drake / Coffin Fly | 8–10 | May-June | Evening |
| Brown Drake | 10–12 | Late May-Early June | Evening |
| Blue Winged Olives | 18–20 | April-August | Mid Morning to Late Afternoon |
| Cahills | 12–16 | May-June | Evenings |
| Slate Drake (Isonychia) | 10–14 | May-September | All Day – Early on cooler days and Later on Warmer days |
| Yellow Drake | 10–12 | June-September | Evening |
| Yellow Stonefly (Sallies) | 14 | June-August | Afternoon |
| Tricos | 20-24 | July-August | Early Morning to Late Morning |
| Whitefly | 10 | August-September | Evening |
| October Caddis | 10–12 | September-October | |
| Ants (high foliage areas) | April-November | ||
| Beetles (high foliage areas) | May-October | ||
| Grass Hoppers (meadow areas) | May-October |
