 Number five. It's already hot, but about to get even hotter. Las Vegas could break its all-time hottest recorded temperature on Sunday at nearly 120 degrees. If Death Valley hits 130 on Sunday, it'll be the hottest temperature ever reliably recorded on Earth, and similar temperatures are expected most of next week. LasVegasCR.KentonPatel says to avoid heat stroke, stay away from why many people visit Las Vegas. Alcohol. Caffeine.