May in Vyborg averages a daily high of 15°C with nights around 6.2°C. Expect roughly 9.9 wet days totalling 43.6mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Vyborg is June–August.
Based on VYBORG, RS (2.9km), 1995–2024. 30 years of May data.