Brutal Winter to Record-Warm May

Syracuse, New York - 2015 Temperatures Through Late June

Daily high and low temperatures (dark blue trace) in 2015 through June 24. Blue arrows highlight period of persistent winter cold. Red arrows highlight period of persistent spring warmth. The average daily temperature range is shown by the brown-shaded area.  (NWS-Binghamton)

We just mentioned the incredible New England snow. That same stubborn pattern contributed to the second coldest February on record dating to 1895 in nine Northeast states, including all of New England, New York, Pennsylvania and Ohio.
February 2015 wasn't just the record coldest February in Syracuse, New York. It was also their coldest single month dating to 1903. Their average temperature during the month, taking into account actual highs and lows, was 9 degrees.
By May, the pattern shifted, making record warmth the talk of the Northeast. New Hampshire, Massachusetts, Connecticut and Rhode Island each sweat through their record warmest May. Cities such as Concord, New Hampshire, and Rochester, New York, set record warm Mays. Syracuse just missed out on that lofty pedestal marking their third warmest May.

https://weather.com/news/news/top-five-coldest-february-midwest-northeast