Lrt's see.In Oklahoma I don't think that temp will be your biggest problem.If the power is out more than three hours the lack of oxygen in the water will start to cause problems.To counter this you can just get a cup and fill it with tank water then dump it back in.Do this 10 or more times every half hour or so. The next problem will be the bio bacteria dying off in the filter.So you should some how get water flowing through the filter.Even if you just dump tank water through it.Keep us posted on how you do. Oh yea,If you have no power how are you reading this??????????