Looking at the temp profile from 7-26, the trout only have <2' of water to live in without at the bottom of the pond that is below 70°F, and we have no idea what the O2 levels are down there. Just because the water is <70°F doesn't mean that there is enough O2 for them to survive. I have had trout stay alive in 80°F water that had aeration and a surface agitator running. So if enough O2 is available it might be possible for them to stay alive all year long in your pond.

There is an O2 system on the market that will put O2 into water below the thermocline and not disrupt the thermocline. But you'd better be sitting down when you see the price of it.