However, the axis tilts at 23.5 degrees, as NASA explains. It’s called the axis, and this rotation is what gives us day and night. The Earth rotates along an imaginary line that runs from North Pole to South Pole. She said that “meteorologists and climatologists prefer to use the ‘meteorological calendar’ because not only do the dates not change - making it easy to remember - but also because it falls in line more with what people think traditional seasons are.” Why does fall equinox happen? “For example, December 10, most people would consider winter, but if you are using the astronomical calendar, technically that is still considered autumn because it is before the winter solstice.” “This makes some dates tricky,” Chinchar says.

Meteorological seasons are defined as the following: March 1 to May 31 is spring June 1 to August 31 is summer September 1 to November 30 is autumn and December 1 to February 28 is winter. These are perhaps the seasons that more people are familiar with,” Chinchar says. “Meteorological fall is different … in that the dates never change and are based on climatological seasons rather than Earth’s angle relative to the sun. Those dates can vary by a day or two each year, but this year are September 22 though December 21,” she says. “Astronomical fall is essentially the time period from the autumnal equinox up to the winter solstice. Fall officially begins on the autumn equinox.īut there are actually two measures of the seasons: “the astronomical seasons” (which follow the arrivals of equinoxes and solstices) and what’s called the “meteorological seasons.”Īllison Chinchar, CNN meteorologist, explains the differences:

Is the autumn equinox the official first day of fall? You can click here to see more cities (rounded down by one minute and adjusted for Daylight Saving Time). Thursday, September 23, while Singapore and Hong Kong clock in at 3:21 a.m. Going farther east, Dubai marks the exact event at 11:21 p.m.Īs we move even farther eastward into Asia, we end up switching days. Out West in Los Angeles and Vancouver, that means it arrives at 12:21 p.m.įor residents of Madrid, Berlin and Cairo, it comes precisely at 9:21 p.m. The equinox will arrive at 19:21 UTC (Coordinated Universal Time) September 22.įor people in places such as Toronto and Washington, that’s 3:21 p.m. More on that farther down in the article.īut first, here are the answers to your other fall equinox questions: Where does the word ‘equinox’ come from?įrom our CNN Fast Facts file: The term equinox comes from the Latin word equinoxium, meaning “equality between day and night.” Precisely when does the fall equinox happen? There’s a good explanation (SCIENCE!) for why you don’t get precisely 12 hours of daylight on the equinox. Well, there’s just one rub - it isn’t as perfectly “equal” as you may have been told. They have long, dark winters and summers where night barely intrudes.īut during equinoxes, everyone from pole to pole gets to enjoy a 12-hour split of day and night. But people close to the poles, in destinations such as the northern parts of Canada, Norway and Russia, go through wild swings in the day/night ratio each year. For people south of the equator, this equinox actually signals the coming of spring.įolks really close to the equator have roughly 12-hour days and 12-hour nights all year long, so they won’t really notice a thing. If you reside in the Northern Hemisphere, you know it as the fall equinox (or autumnal equinox).

On Wednesday, September 22, we enter our second and final equinox of 2021. Twice a year, everyone on Earth is seemingly on equal footing - at least when it comes to the distribution of light and dark. Business & Finance Click to expand menu.

Autumn equinox or fall equinox