September in Kaunas averages a daily high of 17.9°C with nights around 8.4°C. Expect roughly 9.5 wet days totalling 44.2mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Kaunas is May–September.
Based on KAUNAS, LH (5.3km), 1995–2024. 23 years of September data.