Massachusetts's Shawmut Peninsula, upon which Boston is located, lies at the mouths of the Charles and Mystic rivers. The rivers flow into Boston's inner harbor and then into Boston Harbor itself. This harbor is part of Massachusetts Bay and leads ultimately to the North Atlantic Ocean. Boston's Harbor Islands are located in the inner harbor. Shawmut was originally a hilly peninsula that was separated almost entirely from the mainland by marshy swamps. Over the years, Boston's hills were leveled to fill in the back bay marshes; nonetheless, Boston's terrain remains rolling today.
Fog and humidity are by-products of Boston's proximity to water. Rain is frequent throughout the spring and summer, while snow falls regularly throughout the winter, making Boston one of the nation's wettest cities. Atlantic Ocean breezes keep Boston's climate relatively mild compared to other cities in the northeastern United States. Those same Atlantic breezes, however, help rank Boston among the country's windiest cities and occasionally blow into full-fledged storms called "nor'easters."
Area: 48 square miles (2000)
Elevation: 15 to 29 feet above sea level
Average Temperatures: January, 29.3° F; July, 73.9° F; annual average, 51.6° F
Average Annual Precipitation: 42.53 inches of rain; 42.6 inches of snow