Early bird gets the trout
It's obvious... IT'S HOT... EVERYWHERE! Too much, too soon. Luckily we had some snowpack this year because the extra dry spring and now the heat isn't helping. Can't control it though, it is what it is, we just need to adapt.
Mornings will be best in the heat. Water temps are at their coolest then.
Afternoons and evenings see the warmest temps.
Should you stop fishing for trout? No. But that depends.
When to STOP fishing for trout. - I've seen some different opinions on this, I'm not the expert and people posting on places like Instagram are probably not the expert either. The general consensus seems to be when water temps approach the upper 60 degree range trout become more stressed and feed less. Upper 60's would mean 67/68 and higher.
Generally our regional rivers like the North Fork of the Coeur d'Alene and St. Joe Rivers are cool in the morning, but can climb into those ranges later in the day. More so on the North Fork of the Coeur d'Alene due to it's lower elevation, lower gradient, and overall lack of water when compared to places like the St. Joe River.
The Spokane River fairs well in the summer. The lower the Spokane gets, the lower the temps get. More influence from the aquifer and less top spill out of Lake Coeur d'Alene keep temps down. It's one of the better areas in the summer for trout fishing because of this.
Another note worthy river in our region is the Kootenai which flows through Montana and Idaho. We have fished it a bunch and can help you out with where to go, it is more ideal with a boat though FYI.
Other options can include bass and carp fishing. There are TONS of options for both of these.
Don't forget the high country too, alpine lakes are plentiful in the west and stay relatively cool.
It is a good idea to carry a stream thermometer and check the temps in the summer, luckily we have better water temps when compared to others, but it doesn't hurt to be proactive and keep an eye on things.