It looks like 5 states now have a mandatory life jacket wear requirement for cold weather months.The following states are those that I have found. This does not count states that have a mandatory wear requirement for certain bodies of water at all times. If I am missing any, please add them.
Connecticut - Anyone in a manually propelled vessel between October 1st through May 31st.
Maine - Anyone in a canoe or kayak on the Saco River between the Hiram Dam and the Atlantic Ocean from January 1st and June 1st.
Massachusetts - Anyone in a canoe or kayak from September 15th thru May 15th.
New York - Anyone on a vessel less than 21 feet between Nov 1st and May 1st.
Pennsylvania - Anyone on boats less than 16 feet in length or in any size canoe or kayak from November 1st through April 30th while underway or at anchor.