Well its a bit of a story. Spring is start of march to end of may. The spring equinox however;
The March equinox will occur at 05:14 (or 5:14am) Coordinated Universal Time (UTC) on March 20, 2012. This marks the beginning of spring in the northern hemisphere and fall (autumn) in the southern hemisphere from an astronomical viewpoint.
Twice a year, around March 20 or 21 and September 22 or 23, the sun shines directly on the equator and the length of day and night are nearly equal in all parts of the world. These two days are known as the March equinox (vernal in the northern hemisphere) and the September equinox.
Use the Seasons Calculator to find the March equinox date in other time zones or other years.
