It is the water temperature that affects survival after stress (C&R), not whether the fish is a summer or winter run. Since we don't find winter steelhead in warm water, temperature stress only applies to some summer run fish. There isn't a lot of good information on C&R survival on steelhead in the first place, and you can be sure there is less that is specific to summer runs. (BTW, I was gratified to observe than the consensus of expert opinion placed C&R mortality no higher than 5% at the WSC meeting Wednesday night.) Having said there isn't a lot of good information, I'm going to venture that the temperature problem doesn't develop with stream temperatures below 65 degrees F. I've never fished warmer water than that for steelhead, but I have found that steelhead become quite dour in warm water and more reluctant to strike.

I did fish for cutthroat once and found it very difficult to revive the fish for release. Took the water temp and it was 72 degrees. We clipped our flies at the hook bend and counted strikes for awhile. I've decided not to fish when conditions are that stressful to trout.

Hope that helps.