With a spectacular finish, March 2013 represents a huge change from some of the cool early springs of the past few years. Let's compare at Seattle-Tacoma Airport!
March 2012 was dismal. As shown in this plot of temperature (the average highs and lows are shown by the red and blue lines), no day got above 60F and only five days got to or above the normal high in 2012. Many days cooled to below the normal low.
Today (Sunday) should get near 70F over the western lowlands, with clear skies over the entire region (except for some low clouds offshore). Eastern Washington--mid 70s.