The Collaborative International Dictionary of English v.0.48:

Winterly \Win"ter*ly\, a.
   Like winter; wintry; cold; hence, disagreeable, cheerless;
   as, winterly news. [R.] --Shak.
   [1913 Webster]

         The sir growing more winterly in the month of April.
                                                  --Camden.
   [1913 Webster]