Does temperature affect the oxidation of a beer ?
Is a beer at a high temperature, let's say 30C (86F), more susceptible to oxidation that one in low temperature near 0C (32F) ?
I also think that fluctuation in temperature may be a bigger cause of oxidation than just one constant high temp.
My theory; when it is hot the CO2 pressure builds up (expansion caused by heat) and the CO2 escapes from the bottle. When the bottle cools again, the Co2 contracts and the "vacuum" that forms is filled with air from the outside.
Try to store beer cold, or at least cool. Most important is that it must be stored in a dark place.