It’s been good for golfers and joggers, and bad for snowplow drivers and ski resort owners. This December has proved to be one of the warmest on record for New Jersey, following a November that was the warmest for the Garden State in 112 years of weather records. Overall, 2006 is set to become the second-warmest year in New Jersey, behind the record average 55.6 degrees set in 1998. Normally, the average is 52.7 degrees. “We’re on a roll,” said David Robinson, the state climatologist at Rutgers University. Robinson predicted the year will finish with an average of 55.2 degrees. The only truly cold day in December for New Jersey was Dec. 8, when the high temperature was 31 degrees in Newark, 32 degrees in Trenton, and 34 degrees in Atlantic City.