After suffering though a February where the sun shone less than two days and a record amount of snowfall–over three feet–March arrived armed with sunshine and warmer weather. At 1:32 PM EST, in our northern hemisphere, spring, or the Spring or Vernal Equinox became official. Last year, according to NOAA’s Official guide to Times Solstices and Equinoxes, spring arrived much earlier in the day at 7:44 AM EST.

What is an Equinox and why does Spring arrive each year at a different time, or in some cases, a different day?

From nmm.ac.uk:

At the times when the Sun is crossing the celestial equator day and night are of nearly equal length at all latitudes and so we call these dates the equinoxes (= ‘equal night’). In March, as the Sun is moving northwards along the ecliptic, this is called the vernal equinox and in September as the Sun is moving southwards we refer to it as the autumnal equinox. The equinoxes are also the points on the celestial sphere where the ecliptic and equator cross and the vernal equinox is used as the zero point in measuring star co-ordinates.

The Earth takes approximately 365.25 days to go around the Sun. This is the reason we have a leap year every 4 years, to add another day to our calendar so that there is not a gradual drift of date through the seasons. For the same reason the precise time of the equinoxes are not the same each year, and generally will occur about 6 hours later each year, with a jump of a day (backwards) on leap years.

Image – Telegraph