It's the heat. Trout are most active when the water is cold and it is fairly warm outside. What you have to do is cast a worm out with one small weight (or more if needed) and cast it into the current. Let it float downstream and just wait. Sometimes in the summer, you don't feel the fish hit and they just sit in one spot with your bait so be ready when you are reeling in.

try the yozuri pin minnow.i love it!in summer the trout are in fact good eaters , but with the hatches it could be tough catching them .This is when i use the pin minnow beacause its a new look to the fish and i find alot of browns hittting it.

Shane, I agree with you. They can tolerate higher temps for awhile if there is enough oxygen, but become sluggish. I've hooked browns in warm water on nymphs and had them come in without a fight. Point is when the water temps start to get higher than their comfort level (mid-high 60's) they'll try to find cooler water. Temps can drop at night enough to spur activity. Browns love to feed at night.

Here's the secret for summertime fishing any predatory fish (trout, bass, etc.). Warm water sheds oxygen. The warmer the water, the lower the dissolved oxygen, meaning the fish struggle more with breathing. In other words, it's harder to pursue prey for any great distances. That's point #1. Point #2 is that fish are cold blooded. So, when the water warms up, the fish warm up, meaning their heart rate and metabolism also go up. IN OTHER WORDS, they're hungrier, but they're worn out. Trout need colder water than bass, simply because they need more oxygen than bass. But even if the river warms up, they're still hungry and they'll still eat. You just have to put something right in front of their nose -- preferably something that looks like it has a lot of calories in it. So, bigger baits, DEEEP, and SLOOWW, and sight fish directly to the fish you're trying to catch.