September in Tarneit averages a daily high of 17.8°C with nights around 7.3°C. Expect roughly 10.7 wet days totalling 37.7mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Tarneit is November–April.
Based on LAVERTON RAAF, AS (8.8km), 1995–2024. 30 years of September data.