I live in an area where summers are usually in the 70's with days in the 60's and sometimes 90's. Also the winters rarely have frosts with temperature in the 40's normally, but sometimes with week long stretches of sub-freezing temperatures. The coldest one in had a low temperature at 9f. I'm not worried about rainbow trout in the winter, but the summer might be an issue. I'm sure if there is enough oxygen in the summer that the fish would survive, but that would require electricity. This would, however, be an extension of the main system that I'm still contemplating, so I could bring the trout into the main system. Yet, hopefully, the trout could survive year round stocking. If not I could look into koi as a fish, but, koi aren't tasty, as far as I know. However even if I could stock trout year long I think they would require a air infuser, or bubbler.