Massachusetts Bay is part of the Gulf of Maine, which extends from Nova Scotia south to Cape Cod Bay. Massachusetts Bay spans from Cape Ann on the north to Plymouth Harbor on the south, a distance of about 42 miles (68 km). The westmost point of the bay is at the city of Boston. The north shore of Massachusetts Bay is rocky, but the southern shore is sandy. Along the shores are a number of capes and headlands, and off the coast a number of small islands, especially in the entrance to Boston Harbor. Most dive charter boats operate out of the north shore of Massachusetts from Gloucester, Beverly and Winthrop areas. The majority of shipwreck diving sites are off Cape Ann and Boston. In addition, Cape Ann offers a considerable number of shore diving sites.
Massachusetts is considered to have a transitional climate with warm to hot summers and cold, wet winters. Temperatures vary with summer highs of around 27C/81F and winter highs of 2C/35F. There is usually at least one "heat wave" of temperatures in excess of 32C/90F in summer, and at least one very cold period in February with temperatures near or below -17C/0F. New England is classically known as an area with highly unpredictable weather at any time of the year. Although there is year-round diving, the conditions are challenging with cold air temperatures and rougher sea conditions. Generally, summer is the best time to plan a trip to Massachusetts Bay.
Massachusetts Bay offers something to divers of all levels and of any interest. This diverse area reflects a history that includes the pillars of the New England's ocean economy, commerce and fishing. The waters off Boston also contain shipwrecks amassing one of the largest artificial reef areas in the United States due to the 1930s-era Works Progress Administration, which provided for employment during the Great Depression and clean-up of Boston's waterfront. Today, shipwrecks ranging from coal schooners to tug boats to freighters and fishing vessels can be visited by recreational and technical divers alike.
Diving for scallops is a popular activity, and residents with a permit can dive for lobster. In addition, there are numerous beautiful reefs and rock piles that offer underwater photographers the opportunity to see and photograph cold water marine life. Finally, the shipwrecks are plentiful, with numerous shipwrecks in deep water only a few miles offshore. In short, Massachusetts Bay has something to offer for everyone!