The March equinox signals the beginning of spring in the Northern Hemisphere. It marks that special moment when the sun crosses the celestial equator going from south to north. In 2016, this equinox arrives on March 20 at 4:30 UTC, or on March 19 at 11:30 p.m. Central Daylight Time.

At the equinox, Earth’s two hemispheres are receiving the sun’s rays equally. Night and day are approximately equal in length.

2016 has the earliest spring since 1896. The March equinox can come on March 19, 20 or 21. And 2016 has the earliest March equinox since the year 1896. Is it a coincidence that 2012 also had the earliest spring since 1896? No. Recall that both 2012 and 2016 are leap years. But 2016’s spring comes even earlier than the spring of 2012.

With the equinox came a dip in temperatures. After a week of almost-summertime temps, Monday’s high will be 64 with a low of 37. By the end of the week, daytime temperatures will be back in the upper 70s.

Pollen counts will continue to be high this week, according to projections from pollen.com.