Believe it or not, the last New Years Day to feature measurable snow was in 1989 (0.4" of snow) and with the current forecast not showing anything frozen falling on Sunday, we'll be waiting at least one more year before we usher in a new year with flakes flying. New Years Day has had its share of wacky weather though in recent years -- temperatures have averaged out to 44 for a high and 28 for a low since 1992, which isn't terribly much above the "norms" of 41 and 27. However, if you look at things on a year-to-year basis you see some pretty significant swings in temperature from year to year.
Our warmest New Years Day was in 2005 -- a record setting 64 degree high accompanied by plenty of sunshine as a weak front moved through with little cold push associated with it that day (it was a bit cooler on January 2nd). The Mummers Parade could have been better served as a beach party in '05!
We've also had some cold years thrown in -- four of the last 20 years featured a high of freezing or below, including three straight years in the late 90's where the high was either 31 or 32 degrees. Our coldest morning of the last 20 years was in 1998 (which happened to be one of the warmer winters we ever had, believe it or not) where the thermometer dropped to 16 in Philly. We last had a low in the teens in 2009, which also happened to be the last time we failed to reach freezing for a high. We've also been dealing with rain from time to time -- 2003 and 2007 both featured over an inch of rain, postponing the outdoor portions of the Mummers' Parade both years. Luckily, the rainy days have been relatively few in number over the recent past.
All-time, the largest snowfall to occur on January 1st was in 1971 -- 5.3" fell on that day (5.5" total for the storm). However, measurable snow has occurred only fifteen times on the date. Don't expect to make it 16 this year.