The Pool Pros
561-441-9932 - Rob Estell - Rob@thepoolpros.com
Evaporation rates vary depending on many factors such as relative humidity, air temp, water temp, and wind speed. Also running water features such as spitters, water falls, sheer decents greatly increase the surface area of water increasing the amount of evaporation. The evaporation rates of the United States are shown in the pic below.
Please note the study of average rainfall below. With these factual reports it is safe to say that the average rainfall will cancel out the average evaporation. so it would be safe to say that you should, on average, drain water from your pool on a yearly basis as often as you add water.
Natural History
Study site. The primary study site was the Deering Estate, part of the Metro-Dade Park system, in Miami, Fl. I monitored about 20 blackbead plants growing along the shoulders of a roadway through a coastal pine rockland/oak hammock established on Miami oolitic limestone. Average temperatures in Miami range between 10 and 32°C (Tomlinson 1980), with an annual average of ~23°C (Migliaccio 1987). Rainfall averages ~(59 inches) 1500 mm per year, with about 70% of the annual precipitation occurring during the May-to-October rainy season (Migliaccio 1987).
