Over 60 mosquito species occur seasonally in Oklahoma - from March through first frost in November. A few early species prefer cool weather, but the majority of adult mosquitoes are pests during April, May, and June, especially following spring rains. Culiseta mosquitoes first become active in Oklahoma in March with subsequent summer species usually appearing in April and May. Mosquitoes may be present even after the first frost because emerging larval and pupal populations may not be affected by a light freeze. Mosquito populations in Oklahoma are greatly influenced by the weather. Scattered rains may lead to higher populations of mosquitoes in certain areas and not in others. During hot, dry summers there normally are not enough mosquitoes present to cause pest problems.
