Weather & Fly Fishing: How Conditions Affect Your Day

A falling barometer — the kind that precedes a storm — typically triggers a feeding frenzy. Fish sense the pressure drop and feed aggressively before conditions deteriorate. A rising barometer after a front passes is often slower; fish tend to go deep and hold tight until the pressure stabilizes.

Stable, high pressure between weather systems is generally the most predictable time to fish. The feed window may be shorter, but it's more consistent — especially around dawn and dusk.

Overcast days are often the best dry fly days. Clouds diffuse light, reducing shadows and making fish less wary. They'll move shallower and feed more confidently on the surface. An overcast sky also extends productive fishing hours well past the mid-morning shoulder.

Bright sun pushes fish to deeper water or under structure. On sunny days, focus on shade lines, riffles where broken water provides cover, and early morning or evening windows when the sun angle is low.

Many insects hatch within a narrow temperature band. Blue-Winged Olives prefer cool, overcast days in the 45–55 °F range. Pale Morning Duns emerge when air temps climb through the 60s. Matching your outing to the temperature window for the dominant hatch is one of the most reliable strategies in fly fishing.

In summer, extreme heat (air temps above 90 °F) combined with low flows can push water temperatures above the 68 °F stress threshold for trout. On those days, consider resting the fish and fishing early or late — or skipping the trip entirely if conditions are severe.