When is spring today?

There are three versions of 20 12 beginning of spring time, some say it's beginning of spring on February 3rd, some say it's beginning of spring on February 4th, and some say it's beginning of spring on February 5th. Astronomical experts said that according to the astronomical almanac published by the National Astronomical Observatory, the accurate time in beginning of spring this year is 4th 18: 22.