Caddis are also common in summertime. Best activity is late evening until dark, or the first hour of the morning. The lower mile of the Middle Provo just above Deer Creek gets quite a few spawning fish moving up in the fall and winter months. While this is expected of the browns, there is also a fall and winter spawning variety of rainbow trout. Fly fishers often overlook big brown stoneflies, or skwalas.
Large dries can be effective, or cast weighted girdle bugs into pools and riffled water.
A yellow stimulator with a prince nymph or cased caddis can be a good combination. My favorite event of the year is the green drake hatch, which usually comes in early July. This hatch is often of short duration, but the big mayflies can trigger a feeding binge. Water is often still fairly high and trout are in excellent condition, so landing fish can be more challenging than hooking them. Try Quigley cripple patterns in faster water, or soft hackles in slower, shallower pools.