Although most wasps don't typically fly at night, hornets, which are a type of wasp, do. The European hornet, the only species of hornet found in the U.S., flies at night in calm muggy weather.
In many areas, cooler night temperatures prevent many wasps from going out after sunset. Wasps do not fly well when the temperature falls below 50 degrees Fahrenheit. Worker wasps are often attracted to lighted windows in the dark, causing them to collide with the glass. When wasps remain in the nest after dark, they do not sleep through the night. They spend time tending to the nest and to offspring.