Astronomical spring will be ushered in at precisely 4:24 p.m. Monday. But before that, in Chicago, a twice-a-year- phenomenon known as "Chicagohenge" will occur.
According to the Adler Planetarium, "Chicagohenge" is described as the time "when nature and architecture harmoniously come together." It occurs twice a year during the fall and spring equinox, Adler says, "and happens when the Sun directly lines up with Chicago’s east-west facing streets."
The name "Chicagohenge" is inspired by similar events in other cities, where sunrises and sunsets near the autumnal and vernal equinoxes align with a city's street grid, allowing unobstructed views of the sun between the city's buildings.
New York City, Toronto and Montreal all experience similar events, locally known as "Manhattanhenge", "Torontohenge" and "Montrealhenge" respectively.
But according to Adler, Chicago's version of the phenomenon might just be the best one out there.
"Chicago’s streets line up almost perfectly with the cardinal east and west directions on a compass," a blog on Adler's site reads. "This in turn, sets up the perfect stage for Chicagohenge to take place."
How the Phenomenon Works
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"During an equinox, the Sun rises and sets directly to the east and west," the blog continues. "Thanks to Chicago’s perfectly lined grid system, the bi-annual equinoxes mark a time when the Sun rises and sets directly in line with Chicago’s east and west streets, causing Chicagohenge."
The spring equinox will occur at 4:24 p.m. CDT on Monday.
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When and How to See It
"Be on the lookout for Chicagohenge on March 20-23, 2023," Adler says. "The best time to view the Chicagohenge is when looking due east or due west around sunset or sunrise on these days leading up to or after the equinoxes."
According to the NBC 5 Storm Team, sunrise on Monday will occur at 6:54 a.m., and sunset will take place at 7:02 p.m.
Some popular downtown spots to see "Chicagohenge" include intersections between Kinzie Street and Madison Street, though looking down any straight east-to-west street should give a good view of the phenomenon.
"Finding a place to spot Chicagohenge is a no-brainer! Simply find one of Chicago’s east-west facing streets, plop a seat, and enjoy the view," Adler says.