New Jersey light trap data from 1993, a year with unusually high amounts of precipitation, and 1994 were compared with mean light trap counts for the previous 8-10 years in each of 6 locations. The study took place in Iowa. In 1993, Aedes trivittatus and Culex tarsalis populations were unchanged. Anopheles punctipennis and Culex pipiens complex populations were significantly higher, and Aedes vexans populations increased in all 6 sites, significantly so in 2 sites. Species composition was unchanged. In 1994, populations of each of these species were not significantly different from the long-term means. Aedes vexans populations were above average in all sites and populations of the remaining species were below average.