Susquehanna Smallmouth Prime as PA Rivers Warm Into Summer Pattern

What's Biting

What's Next

With water temperatures locked at 78°F and the new moon arriving tonight, the next two to three days set up well for warmwater species on both the Susquehanna and Allegheny systems.

**After-dark catfish and bass:** The combination of warm water, zero ambient moonlight, and moderate river flow creates near-ideal conditions for targeting channel and flathead catfish from dusk through midnight. Fishing the Midwest highlights deep eddies, outside bends, and wood-strewn holes as the summer river holding structure worth focusing on — fresh cut bait or live baitfish on the bottom will be the most consistent approach. Night bass on soft plastics along the same structure is worth a shot early in the evening window.

**Smallmouth daily rotation:** Wired 2 Fish's summer bass coverage lays out the pattern that defines mid-June: fish move shallow in the low-light morning window for topwater and shallow crankbait action, then stage on mid-depth structure — submerged points, ledges, bridge pilings — as temperatures climb through midday. Tactical Bassin (blog) makes a strong case for swing-head jigs and wobble heads fished slowly along rocky bottom in warmer conditions; the technique translates well to the Allegheny's rougher substrate sections when fish are lethargic in the heat.

**Trout:** At 78°F, brown and rainbow trout are under meaningful heat stress on main-stem sections. Field & Stream's temperature guide is direct about the risk: catch-and-release mortality climbs sharply above 70°F, and sustained exposure above that threshold pushes fish into cold-water refugia. If trout are your target, focus exclusively on cold tributary mouths, spring-fed headwater reaches, and pre-dawn sessions where temperatures dip. Keep sessions short and barbless hooks preferred.

**Algal bloom watch:** PA Sea Grant is hosting a June 25 webinar on harmful algal blooms precisely because warm, slow-moving water this time of year is prime HAB territory in Pennsylvania. Before wading slower sections or letting dogs in the water, scan for blue-green surface mats or unusual discoloration. When in doubt, stay out.

Context

A reading of 78°F in mid-June on the lower Susquehanna drainage is on the warm end of typical but not unusual during a sustained heat stretch. Pennsylvania's major river systems generally climb through June, with the Susquehanna mainstem often reaching the upper 70s by late June in average years. An early or persistent warm spell can push that threshold one to two weeks ahead of schedule.

For smallmouth bass — the signature species of both the Susquehanna and Allegheny — mid-June is historically a productive window regardless of temperature. Post-spawn fish have typically recovered by now and are transitioning into their summer feeding rhythm, moving deeper during the heat of the day and chasing baitfish aggressively at dawn and dusk. Flow of 5,070 cfs at USGS gauge 01540500 represents moderate, accessible conditions on the Susquehanna — not flood-stage, not drought-low — which generally supports good smallmouth access along rocky shoals and gravel bars that would be dangerous or submerged at higher water.

The trout picture at this date and temperature is a sharp contrast. PA's limestone spring creeks maintain more stable, cooler temperatures through summer and can hold trout in fishable condition well into July. Freestone streams and main-stem reaches warm quickly without groundwater buffering, and mid-June historically marks the point when serious trout anglers pivot to high-elevation headwaters or very early morning sessions. At 78°F on main-stem sections, that pivot is already overdue.

No current PA Fish & Boat biologist reports for the Susquehanna or Allegheny drainages were available at the time of this report. Seasonal context above is grounded in well-established mid-Atlantic freshwater fisheries norms rather than a direct year-over-year comparison.