Certain types of crickets will spend the winter as nymphs and develop quickly once warm weather arrives. They usually appear as adults and start mating in late spring. They can be heard all the way through late June or early July, which is when they lay their eggs and subsequently die off. Other types of crickets don’t appear as adults until mid to late July and can be heard all the way through the fall, before they lay their eggs and are killed by frost. There is usually a period after the first type dies out and before the second type fully matures, during which neither type can be heard. All types of crickets are active during the night.