Flies, like all living creatures, have a specific range of temperatures where they can thrive. While their activity peaks between 70°F and 80°F, temperatures above 120°F or below freezing can cause dehydration, thermal stress, or death. The temperature at which flies die varies among species. For example, adult house flies become inactive when temperatures fall below 45°F and die when they fall below 32°F. Fruit flies have a slightly higher chill-coma threshold of approximately 50°F and will be unable to continue their normal activities below this point. In general, if the temperatures fall below the fly’s chill-coma threshold, they become immobile and may eventually die. Therefore, it is safe to say that flies can die when exposed to temperatures below their chill-coma threshold.