The earliest known arrival of spring has occurred in Minnesota this March. Snow is gone throughout northern MN and Upper Michigan. Ice out is occurring fast on Minnesota Lakes. The season's first tornado occurred Monday. In the last week, temperatures have been as much as 40 degrees above average. International Falls (on the border with Canada) has had several days with temperatures in the mid to upper 70s (mean high 36, previous record highs in the 50s), and had one night where the overnight low of 60 was equal to the record high for the date. Day after day, record high temperatures are being blown away at weather stations with >100 years of record, by 10-20 degrees. However, it is supposed to cool down soon, so that temperatures will only be 10-15 degrees above average.
In Minneapolis, almost all wind pollinated tree species are in full bloom, including elms and maples (average date first week of May), and oaks look like they are about to open up. I have never seen so many species give off their pollen at once. Spring ephemerals and magnolias are in full bloom! I never thought I would live long enough to see Magnolias bloom in March in Minnesota.
Historically, this was the time of year that we had the biggest snow storms, but March is not even the snowiest month any more in the newly released climate 'normals' with data from 1981-2010.