Boston, MA weather in May
Boston is mild in May, with frequent rain: highs average 67°F and nights drop to about 50°F. Rain falls on about 12 days. A great month for outdoor plans.
- Normal high
- 67°F
- Normal low
- 50°F
- Wet days
- 12
- 3.3 in total
- Muggy days
- 0
- dew point 65°F+
How May changes from start to finish
| May 1 | May 31 | |
|---|---|---|
| Normal high | 62°F | 71°F |
| Normal low | 46°F | 55°F |
| Chance of a wet day | 39% | 37% |
| Sunrise / sunset | 5:39 am / 7:43 pm | 5:10 am / 8:13 pm |
| Daylight | 14.1 h | 15.1 h |
Chance of a wet day: average for the first and last 7 days of the month. Times are local clock time (Eastern Time).
A typical May day
- 6 am54°Fdew point 45°F
- 9 am59°Fdew point 46°F
- Noon62°Fdew point 46°F
- 3 pm62°Fdew point 46°F
- 6 pm60°Fdew point 45°F
- 9 pm57°Fdew point 46°F
NOAA hourly normals (local standard time) from Boston Logan Intl Airport (3 mi away); average wind 11 mph; clear or few clouds in 22% of daytime hours, mostly cloudy or overcast in 61%.
What kind of days to expect
- Comfortable dayshigh 65-80°F and dew point under 60°F14 of 31
- Beach dayshigh 80-95°F, under 0.05 in of rain, afternoon wind under 15 mph2 of 31
- Hot dayshigh 90°F or more1 of 31
- Muggy daysdaily mean dew point 65°F or more0 of 31
- Wet daysat least 0.01 in of rain or melted snow12 of 31
- Notable rainat least 0.10 in7 of 31
- Freezing nightslow 32°F or below0 of 31
- Snow on the groundsnow depth 1 in or more0 of 31
Average days per May, counted from daily records for each year 1991-2020.
Rain in May
Normal precipitation is 3.3 in; a dry May brings about 2.3 in and a wet one about 3.5 in (25th and 75th percentiles). About 2 days bring half an inch or more, and about 1 an inch or more.
How May varies from year to year
- Warmest May, 1991-20201991: average high 73°F
- Coolest May2005: average high 58°F
- Wettest May2006: 12.5 in
- Driest May1991: 0.9 in
- Highest reading95°F (May 18, 2017)
- Lowest reading34°F (May 10, 2020)
From the station's daily records with NOAA quality flags removed; most recent date shown when a reading repeats.
May compared with April and June
| April | May | June | |
|---|---|---|---|
| Normal high | 56°F | 67°F | 76°F |
| Normal low | 41°F | 50°F | 60°F |
| Wet days | 12 | 12 | 11 |
| Comfortable days | 6 | 14 | 12 |
| Daylight | 13.4 h | 14.6 h | 15.2 h |
Highs change by +11°F from April and +9°F into June.
Nearby alternatives in May
- Warmer: Springfield, MA80 mi · high 72°F · 12 wet days
- Cooler: Nantucket, MA89 mi · high 61°F · 12 wet days
How Boston ranks in May
- Normal high320th warmest of 378 cities; 7th of 9 in Massachusetts
- Wet days262nd driest of 378
- Comfortable days156th most of 339
What to pack for Boston in May
- A rain jacket or umbrella – rain on about 12 days
Heating and cooling
May has 234 heating degree days and 29 cooling degree days (base 65°F), 4% of the year's total heating and cooling demand.
Questions
How cold is Boston in May?
The normal high is 67°F and the normal low is 50°F. From 1991 to 2020 the coldest May reading was 34°F (May 10, 2020).
Does it rain a lot in Boston in May?
About 12 days in May have at least 0.01 in of precipitation, and the normal total is 3.3 in. The wettest May in 1991-2020 was in 2006 (12.5 in); the driest was in 1991 (0.9 in).
Is May a good time to visit Boston?
May ranks 1st of 12 months on our comfort score for Boston (71 out of 100). It has about 14 comfortable days and about 1 day at 90°F or hotter. The best months are May, June and September.
Where the numbers come from
- Temperature, rain, snowfall, frost dates, humidity and wind by hour and cloud cover: Boston Logan Intl Airport (USW00014739), 2.5 mi E of the city center, 12 ft . NOAA normals and daily records, 1991-2020.
- Snow depth: Hingham (USC00193624), 12 mi SE of the city center, 35 ft . NOAA normals and daily records, 1991-2020.
- Daily humidity and wind: Gen E L Logan International Airport (725090-14739), 2.5 mi E of the city center, 11 ft . Hourly observations, 1991-2020.