Fall inches closer as summer fades out, with September marking the season's official return to the Chicago area.
The autumnal equinox, also referred to as the September or fall equinox, signals the shift between the two seasons. The first official day of fall will arrive at 8:04 p.m. Sept. 22 for the Northern Hemisphere, according to the Old Farmer's Almanac.
The equinox marks the point when "daytime and nighttime are roughly equal in length," according to Chicago's Adler Planetarium.
The planetarium also noted that the sun will rise later and set earlier throughout the month following the equinox.
As the hours of sunlight lessen, signs of fall will begin to emerge. According to the almanac, leaves start to change colors and drop due to the amount of daylight and photosynthesis, rather than weather conditions, such as temperature.
Sept. 22 also will mark the appearance of the Chicagohenge, the city's celestial event that happens only twice a year.
According to the planetarium, the Chicagohenge showcases the point when the sun directly lines up with Chicago’s east- and west-facing streets. Chicagoans will be able to see the phenomenon until Sept. 25, the planetarium said.
Feeling out of the loop? We'll catch you up on the Chicago news you need to know. Sign up for the weekly> Chicago Catch-Up newsletter.