Keep roof gutters clean and free of anything that keeps them from draining. Repair window and door screens. Most biting activity occurs at dawn and dusk. Other factors being equal, there is less risk at midday. Mosquito activity is higher at temperatures above 50-55 degrees, especially when the warm period is preceded by one or more cool nights.
Mosquito activity is higher under conditions of high humidity.
Mosquitoes are more prone to leave vegetative cover and seek blood in high humidity. No wind means greater mosquito activity. DEM began its weekly mosquito trapping and testing program on June 1. Over 16,000 mosquitoes have been tested to date, from traps set at sites statewide, with a greater number in the South County and East Bay areas. The most recent results come from 1,005 mosquitoes trapped September 20 and separated into 60 groups, or pools, for testing.