CBS 3 Springfield Weather - Every calendar one would go purchase for 2007, turning to March, would reveal the first day of Spring in its traditional spot on March 21st. In truth, the first day of Spring is in fact on the 21st...but only 8 minutes into that day...in Brittain.

Here in the USA, we're set back 4 hours in the time zone scheme from the UK (everyone by longitude has it's own zone for adjusted time). This would put us at 8:08pm (or 8:07pm depending on how serious your calculations are). This way, because of our time zone scheming-- which is normally most helpful many other ways (not the least of which keeping lunchtime in sunlight), people all over the Earth experience the true 'First Day of Spring' at different times.

Remember, 'Spring' wasn't decided upon by government order, or a political line in the sand, but it's an astronomical denotation. It marks out the exact time when the Sun would shine directly over the Equator on it's way up north toward the Tropic of Cancer (the Sun's movement shining directly over the Earth's equator happens only two times per year, with the other being on the first day of Fall). This is all well and good, but there are a few problems when trying to get this down on a calendar:

A year is not an even number of days; The Earth follows a somewhat elliptical orbit that isn't even a whole-number of days long; This elliptical orbit itself is skewing around over the centuries (ever so slightly), causing the Earth's axis to always point in a different direction (kind of appearing like a constantly spinning top that isn't at 'top' speed).

It's a big mess. It's a good thing we're talking about tiny fractions adding up slightly over time.

The seasons themselves aren't equally spaced in timed as well. At this point:

Winter is about 89 days long.

(remember, nothing is ever a nice round number in astronomy)

Spring is near 93 days, Summer about 93.5 days, and Fall almost 90 days. Because of all the aforementioned reasons (and thanks to the tireless efforts of empassioned people who should really have better things to do), these seasons are constantly changing their lengths. Spring is being reduced by about 1 minute per year, and Winter about 30 seconds. Summer is gaining the minute, and Autumn the rest.

It's not easy putting all that down on a calendar for the exact "First" day of Spring now, is it?

According to those who do these sort of calculations, the "real" first day of Spring only hit on March 21st 36 times in the 1900s. Moreover, the next time Spring will actually begin on March 21st in the USA isn't until 2102-- so none of us will be around to see another one (okay most of us won't).

One last item, in 2016, the First Day of Spring will begin on March 19th. I wonder if that's planned on the calendar yet?