In western Massachusetts, jackets and ties are rarely expected for men at restaurants. In general, New Englanders tend to dress slightly more formally than their Midwest or West Coast counterparts for special events. Jeans and sneakers are acceptable for casual dining and sightseeing just about anywhere in the area. Always come with sneakers or other flat-heeled walking shoes for pounding the pavement in urban areas, and with good shoes or boots for hitting the area's many hiking trails.
In spring and fall, pack at least one warm jacket and sweater, since moderate daytime temperatures can drop after nightfall. Bring shorts for summer, which can be quite humid. You need a warm coat, hat, scarf, and gloves in winter; boots for often slushy streets are also a good idea. Western Massachusetts has among the coldest and snowiest weather in the Eastern United States, so pack particularly warm gear if spending much time here.