Chicago's downtown streets are about to put on a show. This Tuesday, September 22, the sun will drop directly between the Loop's skyscrapers during the autumnal equinox, creating the striking visual effect known as Chicagohenge, when daylight and nighttime hours fall roughly even across the globe.
The 2026 equinox lands precisely on Tuesday, according to U.S. Naval Observatory calculations reported by KNPR, marking the moment Earth's equator lines up directly with the sun before Northern Hemisphere daylight begins its slow retreat toward winter. FOX 32 Chicago reports that Chicagohenge is returning with its signature framing of the city grid.
The reason Chicago gets this effect at all traces back to how the city was built. The Adler Planetarium has explained that Chicago's urban street grid runs along true cardinal directions, letting the sun slide neatly between downtown towers during sunrise and sunset on both equinoxes each year, per the same KNPR report. Michelle Nichols of the Adler Planetarium noted that the height of the buildings and the width of the streets work together to accentuate the framing of the sun.
A Grid Built for This, By Accident
Nobody designed Chicago's streets with sunsets in mind. The city's unified street numbering system dates to 1909, based on a proposal from Rogers Park resident Edward P. Brennan, which set the intersection of State and Madison streets as the zero-point for the entire address grid, according to historical context from Chicago L.org. Brennan pushed for the system to address duplicate street names and confusing numbering left over from Chicago's merger with surrounding townships.
That grid's roots run even deeper, to an original plat map designed by James Thompson, Chicago L.org notes. The payoff for that paperwork shows up nearly two centuries later in Chicago's cardinally oriented east-west street grid, since most gridded cities carry slight angular deviations from true east-west lines.
Not the Same Show as Manhattanhenge
Chicagohenge often gets compared to New York's better-known “Manhattanhenge,” but the mechanics are different. Manhattan's street grid sits rotated roughly 30 degrees northeast of true east-west alignment, which is why its solar alignment happens in May and July instead of on the equinoxes, as EL PAÍS English has reported. Axial tilt combined with a city's street orientation ultimately determines whether its own “henge” lines up with the equinoxes or the solstices.
The name Chicagohenge itself borrows from England's prehistoric Stonehenge, which was built to align with the sun during solstices, according to Secret Chicago. Chicago's modern architectural version instead lines up twice a year at the equinoxes.
Best Spots to Watch, and What Comes Next
For anyone hoping to catch it in person, Madison and Randolph streets are viewing locations for framing the setting sun. People line Michigan Avenue, and Millennium Park is another viewing spot.
Worth noting: even on the equinox itself, day and night aren't perfectly equal. Atmospheric refraction bends sunlight as it passes through the atmosphere, so daylight and darkness run slightly unequal despite the sun sitting directly over the equator, according to FOX 32 Chicago. That refraction effect stretches visible daylight a few extra minutes beyond the geometric sunrise and sunset times.
Chicagohenge will be a celestial draw in the sky this week.
