National Weather Service Weather Forecast Office

The season of spring officially arrives at 12:14 AM CDT Tuesday, March 20, 2012,

or, 11:14 PM MDT Monday, March 19, 2012 for those in the Mountain Time Zone.

This marks the arrival of what is called "Astronomical Spring", as compared to

"Meteorological Spring" which began March 1. Meteorological spring is defined as

the months of March, April, and May.