West Nile and encephalitis are present in Florida during the mosquito season — which is just about any time when the temperature hasn’t been below 65° F. for a few days, although skeeters are more numerous during late Spring, Summer and early Fall.
Mosquitoes like protected areas: lee sides of homes with shrubbery in the early morning and evening, forests and woodlands most of the time, and swamps and marshes (particularly at night). In addition to mosquito-borne diseases, wetlands tend to have a lot of deer flies and horseflies, and woodlands the ever-popular ticks and redbugs (chiggers).
Wear long sleeves if possible, and use an insect repellent that contains DEET. Forget the “natural” repellents and Skin-So-Soft®; they don’t do the job in areas that really have bugs. Avoid wearing scents — after shaves, perfumes — and using scented soaps and shampoos. They attract unwanted arthropod attention.
In the woods, or moving through shrubbery or brush, wear long pants, tucked into socks, if possible, and spray the legs liberally with repellent. WARNING: DEET will dissolve some synthetics, and you don’t want it in your eyes. Cotton is safest (and coolest).
For lots more information: West Nile Virus and Encephalitis