You'll need clothing appropriate for the New England climate, although it may not be necessary to bring it all with you during Orientation week. It's likely to be very warm when you first arrive in August and very cold during finals week in December. Consider packing winter clothes in a box that can be mailed to you when the weather turns colder. Expect to need a winter coat, boots, hats, and gloves during the winter season.
Remember: "There's no such thing as bad weather, only inappropriate clothing!"