There are lots of theories on why salmon and steelhead jump, but I dont believe anybody knows why, for sure. In my experience, especially with salmon, as the weather (and the water) cools, the bite will get hotter. Be persistant,you will catch fish.Pay attention, details and subtle clues are important,(watch what the older guys are doing,look for fish flashing,rolling ect).Find the water that hasnt been pounded all day(hike in to places most wont,cover lots of water).Use good bait,(the crappy eggs at bi-mart arent worth the money,get some live sandshrimp instead).Just my opinion,based on my own experience.Good luck