Chicago, Illinois: freeze dates & growing season

Three different things get called “Chicago” here, so this page is explicit about all three: the metro label (Chicago), the anchor geography (Census ZCTA 60602, a downtown ZIP-code area), and the climate record (the NOAA station below). Windows are calculated from the station — not from your street address.

Climate basis: NOAA station Chicago Northerly Is, IL (USC00111550), 2 mi (3 km) from the ZCTA 60602 centroid, elevation 583 ft, on the 1991–2020 climate normals.
Last spring freezeApril 101-in-10 after Apr 25
First fall freezeNovember 51-in-10 before Oct 24
Frost-free season208 daysmedian at 32°F
Hard freeze, 28°Apr 1Nov 15kills even hardy greens
USDA zone6b-5 to 0°F winter low not frost timing

The year

  • indoors under lights
  • in the garden
  • frost-free season
  • 1-in-10 years still freeze to Apr 25
The Chicago year: hatched areas are the freeze-likely seasons in 1991–2020 normals.
What that means in practice
All 79 crops in Chicago

These windows describe typical years (1991–2020 climate normals), not this year's forecast. Freezes happen outside them — especially in frost pockets, valleys, and urban edges. Watch the forecast before committing tender plants.

Check a specific ZIP instead

Metro climates vary — elevation, water, and urban heat shift freeze dates by days to weeks. Look up your exact ZIP:

Nearby reviewed metros

Milwaukee, WI · Madison, WI · Grand Rapids, MI · Indianapolis, IN · Detroit, MI