Spring begins!

Next, March 20, begins the spring. Exactly at 23:45 am Friday.
This seasons are 92 days and 18 hours and it will finish on June 21 with the start of summer.
 It´s the season of year when the days get longer, improve temperatures, flowers field...
 Why begins exactly that day and time?
What does the term "spring" mean?
Do you want know more curiosities?
Hare you have some links with interesting information.

Primavera. Página del Ministerio de Fomento.
Primavera. Wikipedia.
Primavera. Curiosidades.
Primavera. Video-animación explicativo. (Para infantil)
Canciones para trabajar la primavera en el aula.