Autumn has officially begun across the Northern Hemisphere, but when will the Chicago area start to see leaves changing into fall colors?
As of this week, most of the Chicago area is likely seeing minimal changes in fall foliage, according to Smoky Mountains National Park. However, there could be a shift by next week.
According to the website's map, the Chicago area will start to see patches of fall colors beginning Sept. 27. By the week of Oct. 4, the area will have partial coverage of foliage.
The week of Oct. 11 trees around Chicago will likely be nearing their peak of foliage, the map shows, while the fall colors hit their height the week of Oct. 18.
By Oct. 25 into November, most of the foliage will be past its peak throughout Illinois, according to the map.
Though temperatures are beginning to drop around Chicago, the leaves changing colors is caused by the decreased levels of sunlight during the day, according to the Illinois Department of Natural Resources.
The spring and summer sunlight fills the leaves with chlorophyll, which gives them the green appearance, IDNR says. As hours of sunlight drop, the plants receive less chlorophyll, causing them to appear tones of orange, red and yellow.
Here's a list of state parks and recreational areas around Chicago for some of the best views of the fall foliage, according to IDNR:
- Adeline Jay Geo-Karis Illinois Beach State Park
- Buffalo Rock State Park
- Chain O' Lakes State Park
- Channahon State Park
- Des Plaines State Fish and Wildlife Area
- Gebhard Woods State Park
- Goose Lake Prairie State Natural Area
- Heidecke Lake SFWA
- Illinois & Michigan Canal State Trail
- James "Pate" Philip (Tri-County) SP
- Kankakee River State Park
- Mazonia-Braidwood State Fish and Wildlife Area
- Moraine Hills State Park and McHenry Dam State Park
- North Point Marina State Recreation Area
- Silver Springs State Fish and Wildlife Area
- Volo Bog State Natural Area
- William G. Stratton State Park
- William W. Powers State Recreation Area
The first official day of fall is Sept. 22. The autumnal equinox, also referred to as the September or fall equinox, arrives at 2:21 p.m. Wednesday for the Northern Hemisphere, according to the Old Farmer's Almanac.
According to the Adler Planetarium in Chicago, the autumn equinox marks the point when "daytime and nighttime are roughly equal in length."
"If you’re in the Chicago area," Karen Donnelly writes in the Adler Skywatch, "you may be noticing that the Sun rises later and later—and sets earlier and earlier—each day this month."
"Actually, in the Northern Hemisphere the Sun has been rising later and setting earlier since the summer solstice," Donnelly writes, "but from the autumnal equinox on, the night-sky time will last longer than the daylight time until the next vernal equinox. We’ll keep gaining dark-sky viewing time until the winter solstice on Dec. 21."
It also marks the appearance of Chicagohenge in Chicago, this year happening between Sept. 22 and 25. Donnelly describes the twice-yearly event as a celestial phenomenon marking the point when you can see the sun rise or set directly between downtown buildings on east- and west-facing streets.
Cooler temperatures have also arrived for the start of fall in the Chicago area.
On Wednesday and Thursday, showers are possible throughout the area, with high temperatures in the mid-60s and lows dropping to near 50 degrees.
Strong winds Wednesday could bring gusts of up to 45 mph near Lake Michigan Wednesday afternoon and into Thursday morning. Flooding and very dangerous waves are expected along the lakefront.
Things should begin to warm back up a bit by Friday, according to extended forecast models.