September in St. Petersburg averages a daily high of 31.4°C with nights around 25.2°C. Expect roughly 14.1 wet days totalling 178.5mm. Demanding conditions — pack for it and plan indoor options.
Across the year, the best time to visit St. Petersburg is November–April.
Based on ST PETERSBURG ALBERT WHITTED AIRPORT, FL US (5.3km), 1995–2024. 27 years of September data.