Chicago, Illinois: planting zone & frost dates
Chicago is in USDA plant hardiness zone 6a, where the average coldest winter night reaches -10 to -5°F (-23.3 to -20.6°C). The typical last spring frost is around Apr 17 and the first fall frost around Nov 1.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | Apr 25 | Oct 24 |
| Typical planning date (30% risk) | Apr 17 | Nov 1 |
| Median (50%) | Apr 10 | Nov 5 |
How to read this: after the spring "10% risk" date, a 32°F frost happens in only about 1 year in 10. In fall, the "10% risk" date is the early end — a frost before it happens about 1 year in 10.
Frost data comes from NOAA station CHICAGO NORTHERLY IS, IL (USC00111550), 4.1 mi (6.6 km) from the city center and 10 ft lower than the city center (-3 m). Record used for the 1991–2020 normals: 15 years.
Hardiness zone across Chicago
Chicago spans more than one half-zone. Share of the city's land area by zone (via its 55 ZIP codes): 6a (89%), 6b (11%). The headline zone is the one covering the most land. Look up your ZIP for your exact zone.
ZIP codes in Chicago and their zones
| ZIP | Zone | Share of city land |
|---|---|---|
| 60617 | 6a | 6.0% |
| 60628 | 6a | 4.8% |
| 60018 | 6a | 3.5% |
| 60633 | 6a | 3.5% |
| 60609 | 6a | 3.4% |
| 60632 | 6a | 3.3% |
| 60643 | 6a | 3.2% |
| 60634 | 6a | 3.1% |
| 60620 | 6a | 3.0% |
| 60629 | 6a | 3.0% |
| 60608 | 6a | 2.7% |
| 60619 | 6a | 2.7% |
| 60638 | 6a | 2.6% |
| 60623 | 6a | 2.4% |
| 60618 | 6a | 2.2% |
| 60639 | 6a | 2.2% |
| 60630 | 6a | 2.1% |
| 60652 | 6a | 2.1% |
| 60637 | 6a | 2.0% |
| 60646 | 6a | 1.9% |
| 60641 | 6a | 1.8% |
| 60655 | 6a | 1.8% |
| 60616 | 6b | 1.7% |
| 60625 | 6a | 1.7% |
| 60636 | 6a | 1.7% |
| 60647 | 6a | 1.7% |
| 60612 | 6a | 1.6% |
| 60621 | 6a | 1.6% |
| 60624 | 6a | 1.6% |
| 60631 | 6a | 1.6% |
| 60649 | 6b | 1.6% |
| 60644 | 6a | 1.5% |
| 60651 | 6a | 1.5% |
| 60614 | 6b | 1.4% |
| 60656 | 6a | 1.4% |
| 60106 | 6a | 1.2% |
| 60622 | 6a | 1.1% |
| 60607 | 6b | 1.0% |
| 60613 | 6b | 1.0% |
| 60615 | 6b | 1.0% |
| 60640 | 6a | 1.0% |
| 60645 | 6a | 1.0% |
| 60653 | 6b | 1.0% |
| 60657 | 6a | 1.0% |
| 60659 | 6a | 1.0% |
| 60626 | 6a | 0.8% |
| 60642 | 6a | 0.7% |
| 60605 | 6b | 0.6% |
| 60660 | 6a | 0.6% |
| 60610 | 6b | 0.5% |
| 60611 | 6b | 0.3% |
| 60601 | 6b | 0.2% |
| 60654 | 6b | 0.2% |
| 60661 | 6b | 0.1% |
| 60602 | 6b | 0.0% |
Vegetable planting calendar for Chicago
Dates are counted from the 30%-risk frost dates above (last frost Apr 17, first frost Nov 1). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Feb 20 – Mar 6 | Apr 24 – May 8 | — | — |
| Pepper | Feb 6 – Feb 20 | May 1 – May 15 | — | — |
| Lettuce | Mar 6 – Mar 20 | Apr 3 – Apr 24 | Mar 20 – May 1 | Aug 23 – Sep 20 |
| Green Beans | — | — | Apr 24 – May 29 | Aug 9 – Aug 23 |
| Sweet Corn | — | — | Apr 24 – May 22 | — |
| Zucchini & Summer Squash | Mar 20 – Mar 27 | Apr 24 – May 8 | Apr 24 – May 15 | Aug 9 – Aug 23 |
| Cucumber | Mar 20 – Mar 27 | May 1 – May 8 | Apr 24 – May 15 | Aug 9 – Aug 23 |
| Carrot | — | — | Mar 27 – May 1 | Aug 9 – Aug 23 |
| Onion | Jan 23 – Feb 6 | Mar 20 – Apr 3 | — | — |
| Potato | — | Mar 20 – Apr 10 | — | — |
| Basil | Mar 6 – Mar 20 | May 1 – May 15 | May 1 – May 22 | — |
| Spinach | — | — | Mar 6 – Apr 3 | Sep 6 – Oct 4 |
| Kale | Feb 20 – Mar 6 | Mar 20 – Apr 10 | Mar 20 – Apr 10 | Aug 23 – Sep 20 |
| Broccoli | Feb 20 – Mar 6 | Apr 3 – Apr 24 | — | Aug 9 – Aug 23 |
| Peas | — | — | Mar 6 – Mar 27 | Aug 23 – Sep 6 |
| Eggplant | Feb 6 – Feb 20 | May 1 – May 15 | — | — |
| Cabbage | Feb 20 – Mar 6 | Mar 20 – Apr 3 | — | Aug 9 – Aug 23 |
| Radish | — | — | Mar 13 – May 1 | Sep 20 – Oct 18 |
| Strawberry | — | Mar 20 – Apr 10 | — | — |
| Beets | — | — | Mar 27 – May 8 | Aug 23 – Sep 6 |
Nearby cities in Illinois
- Cicero — zone 6a, last frost Apr 17, first frost Oct 26
- Evanston — zone 6a, last frost May 2, first frost Oct 14
- Schaumburg — zone 5b, last frost May 6, first frost Oct 8
- Naperville — zone 5b, last frost May 4, first frost Oct 11
- Joliet — zone 6a, last frost Apr 26, first frost Oct 20
- Waukegan — zone 6a, last frost May 4, first frost Oct 12
More: all Illinois cities · other zone 6a cities: Denver, CO, Milwaukee, WI, Colorado Springs, CO, Omaha, NE, Aurora, CO, Lincoln, NE, Fort Wayne, IN, Worcester, MA