The year 2012 is steaming toward the record books as possibly the warmest on record in the Twin Cities.

Driven by an unusually warm July and a freakishly warm March, the average temperature for the year may well exceed the record set in 1931, state climatologist Greg Spoden noted.

That record is 50.83 degrees Fahrenheit. It is the only one above 50 degrees in records going back to 1872. But the average Twin Cities temperature this year, through Friday, was 51.3 degrees.

The second-warmest year on record was 1987, at 49.65 degrees. The years 2005, 2006 and 2010 were also among the 10 warmest on record; last year was 12th.

Merely normal temperatures for the rest of December wouldn't be enough to break the 1931 record, but the forecast calls for temperatures well above normal through Wednesday. To break the record, December would have to end with an average temperature of 24.1 degrees; through Friday it was 29.7.

A monthly or annual average temperature is calculated by determining the midpoint between each day's high and low temperature, and averaging those.

March of this year was by far the warmest ever, distinguished by the earliest 80-degree reading on record (March 17). It was 15.5 degrees above normal. July was the second-warmest in the books.

The Twin Cities, like the rest of the Northern Hemisphere, has been on a long-term warming trend, with the most pronounced temperature increases during the past two decades, particularly in winter and at night.

Bill McAuliffe • 612-673-7646