CBS 21 - Meteorologist Steve Knight
SHOWERS TONIGHT:
It's the 1st Day of Spring! It officially arrives at 10:46AM with the Spring Equinox when the sun is directly over the equator. It will be a warmer day today with increasing clouds and a high in the 60s. Some showers will arrive from the Northwest after 5pm, dampening thing for Friday evening plans. The showers will move out by Midnight with many spots seeing .10" to .25" of rain.
WEEKEND FORECAST:
After a few early clouds, skies will be mostly sunny on Saturday afternoon with a mild high in the low 60s. Clouds will be on the increase on Sunday with a high near 70!
CBS 21 FIRST WARNING WEATHER FORECAST:
Today: Increasing Clouds, Showers After 5PM: High 62
Tonight: Scattered Showers: Low 46
Tomorrow: Mostly Sunny: High 60
Sunday: Increasing Afternoon Clouds: High 70
Spring has officially arrived in the Northern Hemisphere. Today, Friday (March 20), marks the vernal equinox — the astronomical beginning of spring — when the sun crosses directly over Earth's equator, delivering nearly equal amounts of daylight and darkness to every corner of the globe.
According to the Old Farmer's Almanac, the equinox arrives today at 10:46 a.m. EDT. At that precise moment, the sun aligns with the celestial equator, and neither hemisphere is tilted toward or away from the sun.
The word "equinox" comes from the Latin words aequus, meaning "equal," and nox, meaning "night." True to its name, most locations on Earth will experience close to 12 hours of daylight and 12 hours of darkness today.
Why Days and Nights Aren't Perfectly Equal
There's a small catch, though. Day and night aren't exactly equal on the equinox. As the BBC explains, daylight is measured from the first sliver of the sun appearing on the horizon to the last glimpse disappearing below it. Because of light refraction in the atmosphere, some sunlight lingers even after the sun technically sets. This adds a few extra minutes of light to the day.
That means the day with truly equal daylight and darkness — called the equilux — actually arrives a few days before the equinox in most locations.
Two Definitions of Spring
Not everyone marks spring's start the same way. According to Fox Weather, meteorologists define spring as beginning on March 1 and ending May 31. Weather scientists use that system so they can compare temperature data from year to year without the calendar shifting around. Astronomers, on the other hand, track the position of Earth relative to the sun — and by that measure, spring begins today.
Earth's axis is tilted 23.5 degrees, and that tilt is what drives the seasons. Twice a year, at the March and September equinoxes, the tilt is perfectly sideways relative to the sun, sending nearly equal sunlight to both hemispheres.
What Comes Next
From today forward, daylight hours in the Northern Hemisphere will grow longer with each passing day. That trend continues until the summer solstice in June, which brings the longest day of the year. After that, daylight slowly begins to shrink again, leading toward the autumnal equinox in September, when day and night will once again be roughly equal.
For the Southern Hemisphere — countries like Australia, for example — today's equinox marks the opposite: the first day of autumn.
The Almanac also notes an interesting quirk: the equinoxes are the only two days each year when the sun rises due east and sets due west for everyone on Earth, no matter where they live.