September in Geelong averages a daily high of 17.9°C with nights around 6.7°C. Expect roughly 11.6 wet days totalling 39mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Geelong is November–April.
Based on AVALON AIRPORT, AS (16.7km), 1995–2024. 29 years of September data.