The Twin Cities region of Minnesota known for its dramatic seasonal swings experiences some of the most weather-dependent mosquito patterns in the country. Long, frozen winters give way to wet, thawing springs, followed by warm and humid summers that create ideal breeding conditions. Understanding how these weather shifts impact mosquito populations helps residents prepare for seasonal surges and better manage outdoor comfort.
Each year, mosquito season begins as soon as temperatures remain consistently above 50°F. Snowmelt, spring rainfall, and wetland-rich landscapes around Minneapolis, St. Paul, and northern suburbs like Blaine, Shoreview, and Andover contribute to widespread standing water fueling early mosquito hatch cycles. By mid-summer, when temperatures and humidity peak, mosquito development speeds up dramatically, allowing some species to mature in under a week.
Spring (April–May)
As the ground thaws and snowmelt combines with early spring rains, woodland pools and yard puddles form the first breeding sites. Floodwater mosquitoes (Aedes vexans) are among the earliest to appear, often in large numbers following heavy rain.
Summer (June–August)
Mosquito populations reach their highest levels. Warm temperatures in the 70s and 80s, combined with high humidity and frequent thunderstorms, accelerate mosquito life cycles. Species like Culex pipiens, known for transmitting West Nile virus, become more active, especially at dusk and nighttime.
Early Fall (September–October)
Cooler nights gradually slow mosquito activity, but populations may spike following late-season rainfall or warm fronts. Mosquitoes can remain active until the first hard frost—often in early to mid-October.
Winter (November–March)
Cold temperatures and snow cover end mosquito activity, but many species survive winter in egg form. These eggs remain dormant in soil or frozen water, ready to hatch as soon as warmth and moisture return in spring.
