Archive for March 21st, 2011

Spring has started, on March 21!

Monday, March 21st, 2011

Spring is in the air, yayyy!

Besides the sunny weather these days that add up to the ‘spring fever’ feeling, it is also March 21, so yes, spring *did* really start today! And that in itself turns out to be quite special…

Spring starts at the moment that the sun ‘exactly’ reached the equator while ‘moving’ further North, making the day and night both even in length worldwide. This phenomenon is called Vernal equinox.

Even though we all grew up knowing that spring starts on March 21, that ‘fact’ is nowadays more exception than rule…you might think: ‘Huh?’, but it is true: in the past 100 years, a start of spring on March 21 occurred only 1/3 of the years (roughly) while it mostly started on March 20!

The reason for this has to do with the (slight) inaccuracy of the Gregorian Calendar that we have chosen to use, as well as the fact that the Earth’s elliptical orbit is changing its orientation relative to the Sun. has a more in depth analysis from some years ago.

For Europe it means that the actual start of spring will be on March 20 for decades to come (in 2044 it will even be on March 19!)…so it would make sense to change the start of spring from March 21 to March 20, ah? 😉

Hmm, I didn’t know this, did you?