Yellow Breeches Creek – August Stream Report

Location: Cumberland Valley, PA | Report by Precision Fly and Tackle

Get to know Yellow Breeches Creek in August

August brings warm weather and slower flows to the Yellow Breeches, but fishing opportunities remain solid, especially for early risers and evening anglers. Thanks to its limestone influence, the Breeches maintains cooler temperatures in key stretches. Use a thermometer and check water temps regularly. Terrestrial patterns and late-summer caddis and white flies dominate the surface game, while small nymphs and attractors work subsurface.

Stream Level

• Flow: As of August 11–12, approximately 142 cfs—that's about 72% of normal for this time of year
• Watch: Rainstorms may briefly spike flows—keep an eye on gauges before heading out. USGS Gage Height and Discharge Rate – Yellow Breeches Creek

Water Temperature

• Range: Currently hovering in the 60s to low 70s °F (cooler near springs and tributaries)
• Time: Best fishing windows are early morning and just before dusk
• Tip: Carry a thermometer, seeking waters under 66°F (ideally 60–64°F)
  Quitting early when water temperatures exceed 68°F
  

Water Clarity

• Condition: Clear to slightly stained after storms
• Approach: Long leaders, light tippets, stealthy presentations. Use natural patterns on clear days and slightly flashier flies when the water is off-color

Fishing Overview

Late August is a game of timing and subtlety.

• Morning: Trico spinner falls can bring steady but selective rises.
• Midday: Terrestrials—beetles, ants, and small hoppers—keep fish looking up.
• Evening: Caddis, Cahills, and the legendary White Fly hatch can create blizzard-like conditions, with trout feeding aggressively on the surface. These white mayflies draw fish from deep lies, and the action can be fast and furious while it lasts.
  The key is to be in position before the hatch starts and ready with the right pattern.

Please fish responsibly. Trout activity drops sharply above 66 °F. When water temperatures exceed 68°F, survival becomes a concern for trout.

Specifics and Tips

• Best Times: 6–10 AM and 6–9 PM
• Approach: Fish shaded runs, pocket water, and spring-fed areas—trout seek oxygen and cover
• Presentation: Drift terrestrials tight to banks; twitch slightly to trigger strikes
• Wading: Useful and easy in most areas—watch your step during low flows to avoid spooking fish

What's Hatching

• Tricos (early morning spinner falls – size 22–26)
• Caddis (evening hatches – size 16–18)
• White Flies (often emerge toward dusk size 12–16)
• Light Cahills (evening hatches – size 12-16)
• Pale Evening Duns (evening hatches – size 18-20)
• Hexes (evening hatches – size 6-10)
• Blue-Winged Olives (light, mid-day hatches – size 20–22)
• Terrestrials (all day – hoppers, beetles, ants)

Fly Patterns to Use

Dries:

• CDC Trico Spinner – #24
• Hopper – #12–14
• Hi-Vis Beetle – #16
• Parachute Ant – #18
• X-Caddis – #16
• White Wulff – #12–14
• White Fly Comparadun – #12–14
• White Fly Parachute – #12–14
• Purple Haze – #18 (great attractor in mixed hatches)

Nymphs / Subsurface:

• Pheasant Tail – #16–18
• Walt’s Worm – #14–16
• Frenchie – #16
• Zebra Midge – #20
• Hare’s Ear – #16
• Pat’s Rubber Legs – #10 (for deeper pockets and warmwater stretches) 
  

Precision Tips for the White Fly Hatch:

• Get in position before dusk—this hatch often happens fast.
• Fish emergers as the hatch begins, switch to duns mid-hatch, and finish with spinners as light fades.
• Consider swinging soft hackles 30 minutes before the main hatch to target aggressive fish warming up to the event.

Dry Fly Patterns (Surface Stage – Duns & Spinners)

• White Wulff – #12–14 (high-floating and visible during heavy hatches)
• White Fly Comparadun – #12–14 (low-riding, realistic silhouette for selective fish)
• White Fly Parachute – #12–14 (excellent for slow pools and feeding lanes)
• Rusty Spinner – #12–14 (a deadly alternative when fish key on spent adults)

Emergers (Just Below the Surface)

• White CDC Emerger – #12–14 (matches vulnerable stage as flies break through film)
• Snowshoe Emerger – #12–14 (buoyant, buggy profile for picky fish)
• Klinkhammer – White Body – #12–14 (great for when fish are half-sipping emergers)

Nymphs (Pre-Hatch Stage)

• White Nymph – #12–14 (imitates the pale, almost translucent nymph)
• Soft Hackle – White or Cream – #12–14 (swing just before dusk for pre-hatch feeders)