May in Fredrikstad averages a daily high of 17°C with nights around 5.3°C. Expect roughly 10.8 wet days totalling 55.1mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Fredrikstad is June–August.
Based on RADE TOMB, NO (12.7km), 1995–2024. 11 years of May data.