May in Lowell averages a daily high of 21.2°C with nights around 7.5°C. Expect roughly 12.8 wet days totalling 99.7mm. Generally workable, with some weather to plan around.
Across the year, the best time to visit Lowell is May–June.
Based on LOWELL, MA US (4km), 1995–2024. 28 years of May data.