Boston Weather in May

May in Boston averages 20°C (68°F) during the day and 11°C (52°F) at night. Quite a bit of rainfall is typical this month, with around 100 mm (3.9 in) on average. An umbrella is a good idea.

Rainfall in Boston in May

Expect around 12 days of rain based on historical data, with 100 mm (3.9 in) average. When it rains this month, it tends to come down fairly heavily. Showers can be substantial even if they don't last all day.

Temperature in Boston in May

Expect highs of 20°C (68°F) in Boston in May, with nights dropping to around 11°C (52°F). Temperatures can feel cooler in the morning and evening, so layering is often the best approach. With overnight lows of 11°C (52°F), evenings can feel noticeably cooler than the daytime. An extra layer is a good idea, though the cool air makes for a good night's sleep.

Sunshine in Boston in May

The month enjoys around 301 hours of sunshine, creating mostly sunny days with good weather conditions.

Wind Speed in Boston in May

Average wind conditions reach 6 m/s (12 knots) in May. This creates notably windy weather that is clearly felt and can influence daily activities. Keep in mind this is an average. Some days are less intense, while others can be quite gusty.

Average water temperature in May

The water temperature is only 9°C (48°F) this month, cold enough that most people will want to stay out. Hardy swimmers may manage a quick dip, but it won't be comfortable.

For Boston itself, August and September generally stand out with the best circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.