May weather forecastCape Cod National Seashore, MA
May
Weather in May
May amplifies the spring signals in the Cape Cod National Seashore area. The month observes a lasting increase in sea temperatures, signaling a definitive departure from the colder months. Daily average daylight extends further, making room for increased outdoor activities. Dowelled between April's end and June's onset, May makes a natural transition towards the warmth of summer.Ocean temperature
In May, the average ocean temperature is 49.1°F (9.5°C).Note: Dipping into 49.1°F (9.5°C) below 50°F (10°C) needs protective wear, or you'd face cold shock and breathing issues swiftly. Meanwhile, a slight swim around 55.4°F (13°C) feels cold to the bone.
Daylight
In May, the average length of the day is 14h and 34min.On the first day of the month, sunrise is at 5:34 am and sunset at 7:38 pm. On the last day of May, sunrise is at 5:07 am and sunset at 8:08 pm EDT.
Updated: Jun 4, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
In May, the average ocean temperature is 49.1°F (9.5°C). Swimming in 49.1°F (9.5°C) is considered life-threatening. Even a few minutes in 55.4°F (13°C) water is uncomfortable, and swimming below 50°F (10°C) may cause total loss of breathing control and cold shock, depending on a person's physique.
The average day length in May is 14h and 34min.
In May, on the first day of the month, sunrise is at 5:34 am and sunset at 7:38 pm. On the last day of the month, sunrise is at 5:07 am and sunset at 8:08 pm EDT.
Average sea temperature in May
Cape Cod National Seashore, MA
- Average sea temperature in May: 49.2°F
The best month for swimming (with the highest average sea temperature) is August (67.5°F).
The coldest month (with the lowest average sea temperature) is March (39°F).
Average daylight in May
Cape Cod National Seashore, MA
- Average daylight in May: 14h and 36min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).





