By J. Jala | 12:59 AM September 23, 2020
Chilly mornings, shorter days and longer nights.
Nights would be longer after the autumnal equinox, which marks nearly equal lengths for light and dark, on Tuesday (Sept. 22).
An equinox happens only twice a year—autumnal and spring—when the Earth tilts on its axis while rotating around the sun.
Astronomers use the equinox to mark the transition from summer to fall in the Northern Hemisphere, which happens around Sept. 22 or 23 every year.
Live Science reported that while many of us think of the first day of fall as a full calendar day, the equinox itself is a rather fleeting astronomical event. It happens at a precise moment when the sun’s direct rays are straight over Earth’s equator.
This year’s equinox is at 9:31 p.m. on Tuesday.
According to the weather bureau Philippine Atmospheric, Geophysical and Astronomical Services Administration (Pagasa), the fall equinox has no effect on the weather, but signals the start of longer nights “as the sun moves below the celestial equator toward the southern hemisphere.”
The sun will rise further in the southern part of the eastern horizon after the fall equinox.
Nights will gradually get longer until the winter solstice on Dec. 21, which is the longest night of the year.
After the winter solstice, nights will then become progressively shorter until the spring or vernal equinox, when daylight and nighttime hours are almost equal again.
Meanwhile, at the North Pole, the fall equinox heralds in a time of twilight as the sun sinks below the horizon. Come October, the North Pole will be shrouded in darkness until a few weeks before the spring equinox, which happens on March 20, 2021. Then, the sun will rise above the North Pole’s horizon once more.