From the National Weather Service:
An area of rain will move into Southern New England Monday late afternoon and evening. The rain may start as or mix with a period of sleet or freezing rain before changing to rain during the night. The best chance for sleet or freezing rain would be in the East Slopes of the Berkshires and the Northern Worcester Hills. All areas should change to rain during Monday night.
Keep this in mind if you have celebrations planned for Monday night.