Hornets are most active during the spring and summer due to their reproductive cycle. Hornet queens emerge to start building nests and laying eggs in the spring. During the summer, the eggs hatch and develop into adult hornets. These new adults will leave their nests to mate and new fertile queens will be born. These queens are the only ones that will make it through the winter, and once spring arrives again, they will start a new cycle of laying eggs. Hornets work through the day and night. They rest during the early hours of the morning, and are active again after the sun rises.