Saturday’s temperatures left the Chicago area in mid-winter cold, but spring officially begins just two days later as the vernal equinox occurs Monday afternoon.
Meteorological seasons are generally defined as three-month periods starting at the beginning of every three months, while astronomical seasons are aligned with the biennial equinoxes and solstices.
The vernal and autumnal equinoxes mark the beginning of spring and autumn, while the winter and summer solstices define the astronomical beginnings of these seasons, respectively.
The first day of spring and the vernal equinox have roughly the same length of day and night, just like the autumnal equinox in late September. Adler Planetarium.
This year’s vernal equinox will occur on Monday, March 20th at 4:24 PM, marking the astronomical beginning of spring.
From the vernal equinox to the summer solstice, the days are longer and the sky is darker. The summer solstice is the longest day of the calendar year.
Temperatures aren’t likely to top the 20s on Saturday, but it’s starting to feel a little more like spring around the vernal equinox.
After a sunny Sunday with temperatures likely in the low 40s, the sky will be mostly cloudy on Monday as highs approach 50 degrees.