Hatch calendar

Yellow Breeches Creek hatch calendar.

  • Limestone
  • Catch and release (Allenberry) / stocked elsewhere
  • brown trout
  • rainbow trout
  • wild

South-central PA limestone with the most famous catch-and-release stretch in the state at Allenberry. Reliable Sulphur hatches and a strong year-round midge fishery.

Verify with the agency before fishing

Fishing regulations change every season. This page is a summary maintained by Bield — bag limits, exact dates, and species-specific rules must be verified with TCO Fly Shop before each trip.

What's hatching now

May on the water.

  • Midge

    Chironomidae spp.

    Midge
    Peak week
    Year-round
    Intensity
    Heavy
    Time of day
    Midday
    Water temp
    32–60°F · peak 40°F

    Top flies

    Griffith's Gnat #20-24 · Zebra Midge #20-22 · WD-40 #20

    Reliable winter fishing

  • Blue Winged Olive

    Baetis spp.

    Mayfly
    Peak week
    Mar 25 – Apr 25
    Intensity
    Heavy
    Time of day
    Afternoon
    Water temp
    45–55°F · peak 50°F

    Top flies

    Parachute BWO #18-20 · CDC Comparadun #18-20 · Pheasant Tail Nymph #18

    Spring emergence

  • Sulphur

    Ephemerella dorothea / invaria

    Mayfly
    Peak week
    May 20 – Jun 25
    Intensity
    Heavy
    Time of day
    Evening
    Water temp
    55–68°F · peak 62°F

    Top flies

    Sulphur Parachute #16-18 · Sulphur Comparadun #16-18 · Sulphur Sparkle Dun #16

  • Tan Caddis

    Hydropsyche spp.

    Caddis
    Peak week
    Jun 1 – Aug 30
    Intensity
    Heavy
    Time of day
    Evening
    Water temp
    58–72°F · peak 64°F

    Top flies

    Elk Hair Caddis #14-16 · X-Caddis #14 · LaFontaine Sparkle Pupa #14

  • Hendrickson

    Ephemerella subvaria

    Mayfly
    Peak week
    Apr 15 – May 5
    Intensity
    Moderate
    Time of day
    Afternoon
    Water temp
    50–58°F · peak 55°F

    Top flies

    Hendrickson Parachute #12-14 · Red Quill Spinner #12-14 · Pheasant Tail Nymph #14

  • Grannom Caddis

    Brachycentrus spp.

    Caddis
    Peak week
    Apr 25 – May 10
    Intensity
    Moderate
    Time of day
    Afternoon
    Water temp
    52–62°F · peak 56°F

    Top flies

    Elk Hair Caddis #14-16 · Henryville Special #14-16 · LaFontaine Sparkle Pupa #14

  • Light Cahill

    Stenacron / Leucrocuta spp.

    Mayfly
    Peak week
    Jun 1 – Jun 30
    Intensity
    Moderate
    Time of day
    Evening
    Water temp
    60–72°F · peak 65°F

    Top flies

    Light Cahill Parachute #14-16 · Cahill Comparadun #14 · Light Cahill Spinner #14

Full year calendar

Twelve months on Yellow Breeches Creek.

Each row is a hatch species. Bar color = type, opacity = intensity, peak month outlined. The current month is highlighted on the timeline.

JanFebMarAprMayJunJulAugSepOctNovDecMidge — Year-round (heavy)MidgeChironomidae spp.Blue Winged Olive — Mar 25 – Apr 25 (heavy)Blue Winged OliveBaetis spp.Hendrickson — Apr 15 – May 5 (moderate)HendricksonEphemerella subvariaGrannom Caddis — Apr 25 – May 10 (moderate)Grannom CaddisBrachycentrus spp.Sulphur — May 20 – Jun 25 (heavy)SulphurEphemerella dorothea / invariaLight Cahill — Jun 1 – Jun 30 (moderate)Light CahillStenacron / Leucrocuta spp.Tan Caddis — Jun 1 – Aug 30 (heavy)Tan CaddisHydropsyche spp.Terrestrials — Jul 1 – Sep 30 (heavy)Terrestrials(beetles, ants, hoppers)Trico — Jul 25 – Sep 5 (heavy)TricoTricorythodes spp.Blue Winged Olive — Sep 25 – Oct 30 (heavy)Blue Winged OliveBaetis spp.
MayflyCaddisStoneflyMidgeTerrestrial· peak month outlined · intensity = bar opacity · current month highlighted

Hatch species on Yellow Breeches Creek

The bug calendar in detail.

  • Midge

    Chironomidae spp.

    MidgeMidday

    Water-temperature trigger

    30°F3260°Fpeak 40°F80°F
    Duration
    52 weeks
    Also called
    Chironomids · Snowflies

    Top fly patterns

    • Griffith's Gnat #20-24
    • Zebra Midge #20-22
    • WD-40 #20
    • Disco Midge #22

    Year-round food source — the only consistent option on tailwaters in winter. On cold sunny days look for noses sipping clusters in slow water.

  • Blue Winged Olive

    Baetis spp.

    MayflyAfternoon

    Water-temperature trigger

    30°F4555°Fpeak 50°F80°F
    Duration
    6 weeks
    Also called
    BWO · Olive

    Top fly patterns

    • Parachute BWO #18-20
    • CDC Comparadun #18-20
    • Pheasant Tail Nymph #18
    • RS2 #20

    Most reliable Eastern hatch. Two emergences — spring (March-April) and fall (September-October). Best on overcast, drizzly days.

  • Hendrickson

    Ephemerella subvaria

    MayflyAfternoon

    Water-temperature trigger

    30°F5058°Fpeak 55°F80°F
    Duration
    3 weeks
    Also called
    Red Quill · Dark Hendrickson

    Top fly patterns

    • Hendrickson Parachute #12-14
    • Red Quill Spinner #12-14
    • Pheasant Tail Nymph #14
    • Hendrickson Comparadun #14

    First substantial mayfly hatch on most Eastern rivers. Spinner falls in evening can be as productive as the dun emergence.

  • Grannom Caddis

    Brachycentrus spp.

    CaddisAfternoon

    Water-temperature trigger

    30°F5262°Fpeak 56°F80°F
    Duration
    3 weeks
    Also called
    Apple Caddis · Mother's Day Caddis (East)

    Top fly patterns

    • Elk Hair Caddis #14-16
    • Henryville Special #14-16
    • LaFontaine Sparkle Pupa #14
    • Green-bodied Caddis Nymph #14

    First major caddis emergence of the year. Look for clouds of small dark caddis above riffles in late afternoon.

  • Sulphur

    Ephemerella dorothea / invaria

    MayflyEvening

    Water-temperature trigger

    30°F5568°Fpeak 62°F80°F
    Duration
    6 weeks
    Also called
    Pale Watery · Little Yellow May

    Top fly patterns

    • Sulphur Parachute #16-18
    • Sulphur Comparadun #16-18
    • Sulphur Sparkle Dun #16
    • Pheasant Tail Nymph #16
    • Sulphur Spinner #18

    The most important mayfly hatch on Eastern rivers. Reliable emergence + spinner fall every evening for 4-6 weeks. Match the spinners with rusty-bodied patterns.

  • Light Cahill

    Stenacron / Leucrocuta spp.

    MayflyEvening

    Water-temperature trigger

    30°F6072°Fpeak 65°F80°F
    Duration
    5 weeks
    Also called
    Cahill

    Top fly patterns

    • Light Cahill Parachute #14-16
    • Cahill Comparadun #14
    • Light Cahill Spinner #14

    Pale yellow-cream mayfly. Less intense hatch than Sulphur but reliable across many Eastern rivers in late spring through early summer.

  • Tan Caddis

    Hydropsyche spp.

    CaddisEvening

    Water-temperature trigger

    30°F5872°Fpeak 64°F80°F
    Duration
    10 weeks
    Also called
    Spotted Sedge · Cinnamon Caddis

    Top fly patterns

    • Elk Hair Caddis #14-16
    • X-Caddis #14
    • LaFontaine Sparkle Pupa #14
    • Tan Caddis Soft Hackle #14

    Workhorse summer caddis. Heavy emergences and egg-laying flights at dusk through summer. Drop a soft hackle on the swing during the evening.

  • Terrestrials

    (beetles, ants, hoppers)

    TerrestrialAfternoon

    Water-temperature trigger

    30°F6078°Fpeak 70°F80°F
    Duration
    12 weeks
    Also called
    Hoppers · Ants

    Top fly patterns

    • Foam Hopper #10-12
    • Foam Beetle #14-16
    • Para-Ant #16-18
    • Chernobyl Ant #10

    Not a hatch but the most important summer trout food in many Eastern systems. Fish tight to grassy banks and overhanging trees. Hopper-dropper rigs are deadly July through September.

  • Trico

    Tricorythodes spp.

    MayflyMorning

    Water-temperature trigger

    30°F6075°Fpeak 68°F80°F
    Duration
    8 weeks
    Also called
    White-Winged Black · Curse

    Top fly patterns

    • Trico Spinner #20-24
    • Trico Parachute #22
    • CDC Trico #22

    Tiny black-bodied mayfly. The spinner fall — not the dun emergence — is the main event. Look for clouds of spinners over flat water at sunrise.

River info

River type
Limestone
Primary species
brown_trout · rainbow_trout · wild · stocked
Management
Catch and release (Allenberry) / stocked elsewhere
Counties
Cumberland County
Elevation
400 ft
Access
Substantial public access including the famous Allenberry section in Boiling Springs. Year-round catch and release on the lower mile.
USGS gauge 01571000

Sources

Data quality: estimated

Live water temperature & hatch alerts.

Bield Fish reads USGS gauges, watches for the trigger window, and pings you when Yellow Breeches Creek hits the temperature for your target hatch.

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