a lot of it has to do with size of the gear, leader, presentation, and type of water you are fishing. For summer fish we down size everything one to two sizes. My leader drops from 10# to 6#. I move from slower runs to deeper faster riffles, undercut banks, and shade. My hook size goes from a 1 or 1/0 to no biger than a #2 owner, and when they are being picky a #4.
Depends on what the water conditions are. Steelhead are steelhead.
It's just that during summer there comes a point to where the water warms greatly and gets low and clear. Then the fish are seeking oxygen rich environments. Riffles, white water areas, or where creeks come into the river.
In early summer when the water is still cold (Below 50) and a bit high and green I still use the same methods as I do for winters. 8-10# flouro leaders, bright jigs, bigger bright spinners.
Later in Summer (Above 50 deg) I use Smaller hooks, 6-8# flouro leader,
smaller #3 tarnished brass spinners, darker and smaller jigs, smaller yarn balls etc... Think kinda like you would be fishing for trout, same size baits and small hooks(size 2-4) .02
Remember what he said...Steelhead are Steelhead... That they are. Just a smelly, run of the mill stocker trout that happens to make it to the ocean, and back again. Treat them like trout, not like Salmon when fishing for them. Change up often if you know fish are there, but not eating your offering. Cover lots of water, making casts 10"(*inches, not feet!) farther every time...Ect... There are very productive methods of going about it, and the above listees named a few for both seasons. But the general rule in most peoples arsenal is where to look, and what to rig as a starting point. And adapt it to other seasons, or runs. I.E. what is the first thing you will cast at them in the Winter V.S. the Summer? Good info guys.