Martha's Vineyard water temperature

Typically about 74° in August — perfect.

from the buoy in Nantucket Sound, about 15 miles away

perfect

bath-warm 80° and up perfect 72–79° refreshing 65–71° brisk below 65° 74° typical for August

This number comes off Nantucket Sound — the warm side of the island, where State Beach and Oak Bluffs are. South Beach at Katama faces the open Atlantic and swims several degrees colder.

The year at a glance

Swimmable from July through September.

swimmable 30° 40° 50° 60° 70° 80° 74° 37° JFMAMJJASOND January: typically 39° — brisk February: typically 37° — brisk March: typically 41° — brisk April: typically 47° — brisk May: typically 56° — brisk June: typically 65° — refreshing July: typically 74° — perfect August: typically 74° — perfect September: typically 70° — refreshing October: typically 62° — brisk November: typically 52° — brisk December: typically 43° — brisk

Month by month

Month Typical Feels
January 39° brisk
February 37° brisk
March 41° brisk
April 47° brisk
May 56° brisk
June 65° refreshing
July 74° perfect
August 74° perfect
September 70° refreshing
October 62° brisk
November 52° brisk
December 43° brisk

About this reading

The reading comes from the buoy in Nantucket Sound, just off the coast.

Reading from the buoy in Nantucket Sound, about 15 miles away.

Warm water says nothing about surf, rip currents, or bacteria — check local lifeguard flags and advisories.