So Apparently Heat-Waves Kill Your Liquor

I’m on the East Coast, where we currently are having a heat wave. Twice now, I have poured my alcohol (40% ABV vodka) into a glass and sipped on it during the evening, like I usually do. Twice now, after falling asleep, I have awoken after several hours, taken a sip of vodka and thought “What the hell is that? It tastes like water.” It finally occurred to me that there was very little vodka left in the glass, so a large portion has been exposed to the air at very high temperatures (88°F-98°F). Is it possible that the alcohol has evaporated, leaving what tastes like stale water?