There’s a chill in the air in the Chicago area this week, but cooler temperatures aren’t the only milestone the region is hitting as fall approaches.

The autumnal equinox occurs on Sunday, September 22 at approximately 7:44 a.m., but in the Chicago area there are numerous daylight milestones before and after that date.

While most residents would assume that the city will see about 12 hours of daylight and 12 hours of nighttime during the autumnal equinox, that’s not entirely true. In fact, the first day with less than 12 hours of daylight won’t occur until three days later, on September 25, according to TimeandDate.

For daylight lovers, it will be almost six months before we have 12 hours of sunlight again. That date is expected to be March 17, 2025.

Another important milestone on the road to fall occurs on Sunday, September 15. On that date, the sun will set before 7 p.m. for the first time since March 16. The sun will set at 6:58 p.m. that day.

The rest of the month, Chicago loses just under three minutes of daylight each day, with the sun setting just after 6:30 p.m. in late September.

The next milestone is reached on October 21st, when the sun disappears below the horizon before 6pm, at which point we have less than 11 hours of daylight per day.

Those reductions will continue unabated until December, when the city will see just over nine hours of daylight. The earliest sunset of the year will occur in early December, with the sun setting around 4:19 p.m.

After the winter solstice, the area will slowly see more daylight, but will only increase by a few seconds per day until the end of 2024.