Boston weather in May
Temperature, sea and sunshine in May: long-term averages from 30 years of weather data, not a forecast.
Holiday weather in May
Good
Best time to visit: May – September
What is the weather like in Boston in May?
In May, Boston is mild: daytime highs average 18 °C, and nights cool down to about 10 °C. The sea averages 10.4 °C – swimming is only for the hardy. The sun shines for around 7 hours a day. Rain is frequent, with about 11 rainy days and 86 mm in total. All in all, May is a good month for a holiday in Boston.
May compared
How the weather changes from April to June. Tap a month to open it.
More details for May
- Daylight
- 14 h 34 min05:23 – 19:57
- UV index
- 9 · very highclear sky, noon (estimate)All months
- Muggy days
- 0 daysdew point 18 °C or moreAll months
- Wind
- 20 km/haverage daily peakAll months
- Cloud cover
- 64 %on averageAll months
- Hot days
- 0 days30 °C or moreAll months
- Snow days
- 0 days1 cm or more of fresh snowAll months
- Time zone
- UTC−4America/New_York
How the score comes together
- Temperatureweight 50 %100 %
- Sunshineweight 20 %65 %
- Few rainy daysweight 30 %51 %
Each factor is rated from 0 to 100 % and weighted for the travel style “City break”.
What to pack in May
- Sunscreen
- Sunglasses & sun hat
- A jumper for the evenings
- Rain jacket or umbrella
Boston in May: quick answers
Is Boston hot in May?
No. In May, Boston is mild: daytime highs average 18 °C and nights drop to about 10 °C.
Can you swim in Boston in May?
Only if you don't mind cold water: in May the sea averages just 10.4 °C. Comfortable swimming temperatures are not reached at any time of year.
Does it rain much in Boston in May?
Rain is frequent, with about 11 rainy days and 86 mm in total.
Boston month by month
The whole year in BostonAll destinations: USAWhere to go in MaySea temperature in May
Climate averages 1996–2025, not a forecast. Data: Copernicus ERA5 / ERA5-Land via Open-Meteo.com (CC BY 4.0), NOAA OISST, WMO 1991–2020 (NOAA NCEI), GeoNames (CC BY 4.0). Sources & licences