Spring Equinox 2011: When does spring begin?

The spring equinox, when spring officially begins, is at 7:21 p.m. Sunday, March 20.

The days have been growing longer since the winter solstice. On March 20, there will be equal parts of both day and night, marking the spring, or vernal, equinox.

The summer solstice, marking the start of summer and the longest day of the year, will occur at 1:16 p.m. June 21.