Tuesday marks the first day of Spring, at least in astronomical terms, for the northern hemisphere.
Referred to as the Spring or Vernal Equinox, this phenomenon is characterized by day and night lasting roughly 12 hours each. This occurs due to the Earth’s axis and orbit aligning to form right angles in relation to the sun, with the sun’s rays intersecting both Earth’s poles.
This means that the sun will appear to rise and set exactly to the east and west, respectively, since it will be moving northward from a point on the equator. This is why daylight hours will appear to grow longer in the northern hemisphere in the coming weeks. The longest day and shortest night will be on June 20, the summer solstice. This marks the moment when the sun appears at its closest point overhead for those living in the northern hemisphere.
In terms of the vernal equinox, the sun hits the equator on March 19 at 10:06:20 p.m., with the ecliptic and celestial equators aligning. More specifically, the sun will appear directly above the equatorial Pacific Ocean, just to the northeast of West Papua, New Guinea. It is worth mentioning that the appearance of the sun on the horizon is actually an optical illusion. It appears higher than it truly is due to the way its rays bend around the Earth’s atmosphere — an effect called refraction.
While the summer solstice tends to have more cultural significance, the vernal equinox nonetheless promises that meteorological Spring is likely right around the corner.
North Texans should expect astronomical Spring to kick off with some potentially severe weather later this week. The National Weather Service in Fort Worth predicts storms on Thursday afternoon, with chances of high winds and hail south of the I-20 corridor. Meanwhile, temperatures should hover between the 50s and mid-70s into the weekend.
