Most mosquito species in the U.S. increase activity from dusk to dawn, which means you're more likely to get bit if you step outside at that time. People who spend time or live near wooded areas, wetlands or shaded places with standing water, a breeding ground for mosquitoes, are at increased risk of bug bites.

Mosquito activity is generally most intense during the crepuscular hours, which are the periods of dawn and dusk. This is because most common mosquito species, such as the Aedes and Culex, are highly sensitive to the sun's heat and dehydration. The low-light, high-humidity conditions of early morning and late evening provide the perfect environment for them to forage for blood meals without being scorched by the midday sun. During these times, wind speeds also tend to be lower, making it easier for these weak fliers to navigate. However, in 2026, travelers must be aware of the "Asian Tiger" mosquito (Aedes albopictus), which is an aggressive daytime biter that does not follow the standard dawn/dusk rule. To minimize your risk, experts recommend staying indoors or using high-concentration DEET or Picaridin repellents during these peak transition periods. If you are near standing water or in a tropical climate, wearing long-sleeved, permethrin-treated clothing is the most effective defense against the concentrated "swarms" that typically emerge just as the sun begins to set or rise.