Northern California has experienced the driest start to a calendar year since 1921, according to weather officials. A total of 2.3 inches of precipitation fell since December, according to measurements taken at eight weather stations staggered throughout the Northern Sierra. In 1991, 4 inches fell over the same time period, representing the next lowest total. Only 1.32 inches of precipitation has fallen in downtown Sacramento thus far in 2013, which makes it the third driest total since records started being kept — dating back to the 1880s said Tom Dang, National Weather Service meteorologist. The average for January and February …