September in Sarpsborg averages a daily high of 16.7°C with nights around 9.8°C. Expect roughly 11.5 wet days totalling 87.2mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Sarpsborg is June–August.
Based on SARPSBORG, NO (0.3km), 1995–2024. 28 years of September data.