Weather In Tampa – Sep – 2025 Fahrenheit. In tampa, in september, the average water temperature is 84.4°f (29.1°c). Weather.com brings you the most accurate monthly weather forecast for tampa, fl, united states with average/record and high/low temperatures, precipitation and more.

Insights into temperature, precipitation, and weather trends. In tampa, in september, the average water temperature is 84.4°f (29.1°c).