Today Afghanistan and Iran they mark the beginning of their new year نو روز, literally the "new day." For the rest of us we mark the first day of Spring, the day after the vernal equinox.
Christianity like its parent Judaism, did not invent its liturgical feasts out of whole cloth. As Pope Benedict XVI points out in his book Jesus of Nazareth, they took many of the aspects of the nature religions that preceded them and gave them new meaning.
While the U.S. Bishops Conference decided to not celebrate the "Ember Days" any longer, much of the Catholic world still marks the four seasons of the year with these celebrations. These were days of fasting that kept us mindful throughout the year that everything we have comes as gift from God. To quote the preface, "All times and seasons obey your laws" The ember days continue to be celebrated in more rural areas where people have remained more in touch with the cycle of the year.
The English word Ember comes from the Anglo-Saxon ymbren, which means revolution or cycle. While we may no longer fast for three days before the start of each new season year in the U.S., perhaps as we see the flowers beginning to bloom, and the warmer days beginning we should stop today and give thanks to God for the simple beauty of creation.