Each new light bulb for my oven doesn't last long
I appreciated everyone's comments and wanted to follow up with what seems to be the answer.

My latest bulb has not burned out, and it has been 10+ months.

Apparently I'd simply had a streak of bad luck with the bulbs I'd bought.

My hypothesis that my usage or lack of usage of air conditioning in various seasons affected the electricity of the oven seems to be incorrect.

Thanks for all the tips you posted, though.