The Vernal Equinox a.k.a. the First Day Of Spring

Do you know why Spring occurs when it does and that the reason for the season is actually scientific, since the Earth rotates on an axis that is tilted in it's orbit. 

The 23.5° tilt causes the different hemispheres to be at different angles to the sun at different times of the year. In our northern hemisphere on March 20 (sometimes the 19th or 21st) the Vernal Equinox, also referred to as the Spring or March Equinox, is when the sun sits on the plane of the earth's equator.

In the southern hemisphere at this time of year, they would be experiencing the Autumnal (Fall) Equinox. Conversely, we would experience the Autumnal Equinox in September, and the southern hemisphere would experience the Vernal Equinox of course.

In both cases, the Equinox occurs when the Earth's orbit takes it to the point where the sun crosses the Celestial Equator, an imaginary line that runs above the Earth's equator. At this juncture, there are an equal number of hours in the day and night (12 hours), so the Latin word Equinox literally means equal (equi) night (nox).

From here on in, we begin to see longer and longer daylight hours until we reach the Summer Solstice, which is the peak amount of sunlight in our northern hemisphere. 

Of course, we all know that long stretch of darkness at the Winter Solstice, where it gets dark around 4:00 in the afternoon and the sun doesn't arise until 8:30, and that's just around Calgary. Worse as you get into the far north where it stays dark all day. Naturally, the opposite is true wen they get 24 hours of sunlight on the occasion of the Summer Solstice, hence the term "Land Of The Midnight Sun".