The current placeholder for warmest December in Boston is 2006, when high temperatures averaged 41 degrees.

As of midnight Thursday December 10, 2015, Boston temperatures averaged more than three degrees higher than the record at 43.9 degrees.

A pattern of warm December weather will likely continue through the weekend and next week, setting Boston on track to surpass the record for warmest December on record, the National Weather Service said.

However, weather service meteorologist Alan Dunham said it's still too early to tell if this December will be a record-breaker. The month could still end with the freezing winter temperatures New Englanders are accustomed to, he said.


"Even if in the next week we stay above normal, if we get a good chill in here for the last week of the month" December 2015 could still average below the record, Dunham said.

High temperatures are expected to be around 10 degrees warmer over the next five days than the normal December highs in the lower 40s.

As for daily records for high temperatures, Dunham said Boston is most likely to break a record on Sunday. The record high for December 13 in Boston is 63 degrees, which was set in 1984.

Worcester could also break a daily high record on Saturday. The highest temperature on record in the city for December 12 is 63 degrees, set more than 100 years ago in 1911.

More unseasonably warm and sunny weather is on tap for the end of the work week.

Partial cloud cover will likely keep temperatures in the upper 50s in Massachusetts Thursday, Dunham said, and temperatures could reach the lower 60s Friday.

Highs in the mid- to upper 50s and possibly the lower 60s are expected through the weekend before some rain is expected to arrive early Monday, Dunham said.


John R. Ellement can be reached at ellement@globe.com. Follow him on Twitter @JREbosglobe.