Located in Loudoun County, Dulles experiences a humid subtropical climate with four distinct seasons such as mild springs, hot humid summers, and cool winters. These seasonal weather shifts directly influence mosquito behavior, breeding cycles, and population surges across local neighborhoods, wetlands, and wooded areas.
Mosquito season typically begins in late April when temperatures rise above 50°F. Spring rainfall and standing water create ideal breeding conditions, while summer humidity accelerates mosquito development, allowing larvae to become adults in under a week.
Spring (April–May)
Spring rains and warming temperatures trigger the first mosquito hatch.
Standing water in puddles, storm drains, planters, and retention ponds becomes active breeding habitat.
Woodland mosquitoes appear in areas around the Potomac River, Sugarland Run, and residential wetlands.
Summer (June–August)
Peak mosquito season. High humidity and temperatures in the 80s–90s speed up the mosquito life cycle.
Thunderstorms followed by warm, still evenings cause rapid population spikes.
Culex mosquitoes — carriers of West Nile virus — become most active at dusk and nighttime.
Early Fall (September–October)
Mosquito activity remains strong, especially when summer heat lingers.
Rainfall and warm evenings can cause a brief late-season surge.
Activity slows when nighttime temperatures regularly fall below 50°F.
Winter (November–March)
Mosquito activity drops significantly, but eggs remain dormant in frozen or dry conditions.
Warm winter days above 50°F may cause short-lived appearances of adult mosquitoes.
