What Is the Spring Equinox?

The first day of spring has arrived with mostly sunny skies and warmer temperatures.

Today, the Orange County area will see highs ranging from 60 to 65 near the cost and 66 to 71 inland. We'll see lows tonight from 44 to 51 with light winds.

On Wednesday, it will again be mostly sunny and still a bit warmer, with highs ranging from 62 to 67 near the coast and 71 to 76 inland. Thursday will be more of the same, except for fog in the morning.

As the weekend arrives, so does the possibility of rain. The area will see a chance of rain Saturday night and during the day Sunday.

Facts About The Equinox

The word equinox is derived from the Latin words meaning “equal night.” The spring and fall equinoxes are the only dates with equal daylight and dark as the Sun crosses the celestial equator.

The March equinox signals the beginning of spring in the Northern Hemisphere and autumn in the Southern Hemisphere. It marks that special moment when the sun crosses the celestial equator going from south to north. In 2012, this equinox comes early. It’ll be on March 20.

Why is the equinox early? The reason, according to earthsky.org, is partly because 2012 is a leap year. If this year weren’t a leap year, this equinox would come on March 21. The equinoxes for the coming three years – 2013, 2014, 2015 – will all fall on March 20 as well. But – with each passing year – each equinox will come nearly 6 hours later by the clock. In the year 2016, the equinox would fall on March 21 – if 2016 weren’t a leap year.

(Video: How an Equinox Works.)