July typically offers the warmest temperatures on Martha’s Vineyard, an island south of Cape Cod, Massachusetts. Average highs reach the low 80sF (high 20sC), while overnight lows settle in the mid-60sF (around 18C). Sea breezes moderate the heat, creating comfortable conditions ideal for outdoor activities. Rainfall is generally moderate, with brief showers possible. The Atlantic Ocean water temperature reaches its most pleasant levels for swimming during this month.
This period represents peak season for the island. The agreeable climate attracts visitors seeking beach vacations, sailing, watersports, and other outdoor pursuits. Historically, July has also been a popular time for social events and festivals on the Vineyard. The combination of favorable weather and a vibrant cultural scene contributes significantly to the island’s summer economy.