Evanston, Illinois: planting zone & frost dates
Evanston 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 May 2 and the first fall frost around Oct 14.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | May 11 | Oct 5 |
| Typical planning date (30% risk) | May 2 | Oct 14 |
| Median (50%) | Apr 26 | Oct 21 |
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 BOTANIC GARDEN, IL (USC00111497), 8.0 mi (12.8 km) from the city center and 33 ft higher than the city center (+10 m). Record used for the 1991–2020 normals: 29 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Evanston
All 3 ZIP codes covering Evanston are in zone 6a.
Vegetable planting calendar for Evanston
Dates are counted from the 30%-risk frost dates above (last frost May 2, first frost Oct 14). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Mar 7 – Mar 21 | May 9 – May 23 | — | — |
| Pepper | Feb 21 – Mar 7 | May 16 – May 30 | — | — |
| Lettuce | Mar 21 – Apr 4 | Apr 18 – May 9 | Apr 4 – May 16 | Aug 5 – Sep 2 |
| Green Beans | — | — | May 9 – Jun 13 | Jul 22 – Aug 5 |
| Sweet Corn | — | — | May 9 – Jun 6 | — |
| Zucchini & Summer Squash | Apr 4 – Apr 11 | May 9 – May 23 | May 9 – May 30 | Jul 22 – Aug 5 |
| Cucumber | Apr 4 – Apr 11 | May 16 – May 23 | May 9 – May 30 | Jul 22 – Aug 5 |
| Carrot | — | — | Apr 11 – May 16 | Jul 22 – Aug 5 |
| Onion | Feb 7 – Feb 21 | Apr 4 – Apr 18 | — | — |
| Potato | — | Apr 4 – Apr 25 | — | — |
| Basil | Mar 21 – Apr 4 | May 16 – May 30 | May 16 – Jun 6 | — |
| Spinach | — | — | Mar 21 – Apr 18 | Aug 19 – Sep 16 |
| Kale | Mar 7 – Mar 21 | Apr 4 – Apr 25 | Apr 4 – Apr 25 | Aug 5 – Sep 2 |
| Broccoli | Mar 7 – Mar 21 | Apr 18 – May 9 | — | Jul 22 – Aug 5 |
| Peas | — | — | Mar 21 – Apr 11 | Aug 5 – Aug 19 |
| Eggplant | Feb 21 – Mar 7 | May 16 – May 30 | — | — |
| Cabbage | Mar 7 – Mar 21 | Apr 4 – Apr 18 | — | Jul 22 – Aug 5 |
| Radish | — | — | Mar 28 – May 16 | Sep 2 – Sep 30 |
| Strawberry | — | Apr 4 – Apr 25 | — | — |
| Beets | — | — | Apr 11 – May 23 | Aug 5 – Aug 19 |
Nearby cities in Illinois
- Chicago — zone 6a, last frost Apr 17, first frost Nov 1
- Cicero — zone 6a, last frost Apr 17, first frost Oct 26
- Waukegan — zone 6a, last frost May 4, first frost Oct 12
- Schaumburg — zone 5b, last frost May 6, first frost Oct 8
- Naperville — zone 5b, last frost May 4, first frost Oct 11
- Elgin — zone 5b, last frost May 1, first frost Oct 12
More: all Illinois cities · other zone 6a cities: Chicago, IL, Denver, CO, Milwaukee, WI, Colorado Springs, CO, Omaha, NE, Aurora, CO, Lincoln, NE, Fort Wayne, IN
Evanston gardening questions
When is the last frost in Evanston, IL?
Plan around May 2. At NOAA's Chicago Botanic Garden, IL station, 8.0 mi from the city center, there is a 30% chance of a 32°F frost after that date. Half of springs have their last frost by Apr 26, and after May 11 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Apr 13. The 90% and 10% dates are 30 days apart, close to the 36-day median for cities on this site.
When should I plant tomatoes in Evanston, IL?
Start seeds indoors Mar 7 – Mar 21 and set transplants outside May 9 – May 23, once nights stay above 50°F and the soil is near 60°F. That leaves 165 days between the 30% frost dates, enough for most varieties including 80–85-day slicers. More: tomato planting dates by zone.
How long is the growing season in Evanston?
About 176 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 155 days, and in 1 year in 10 it runs 197 days or more. In fall there is a 10% chance of frost by Oct 5 and a 30% chance by Oct 14. That ranks 8th longest of 14 Illinois cities on this site.
When should I plant a fall garden in Evanston?
Count back from the first fall frost (Oct 14): transplant broccoli Jul 22 – Aug 5; sow kale Aug 5 – Sep 2; sow lettuce Aug 5 – Sep 2; sow radishes Sep 2 – Sep 30. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Nov 1. How the math works: succession and fall planting.
Did Evanston's hardiness zone change on the 2023 map?
Yes. Most of Evanston was zone 5b on the 2012 map and is zone 6a on the 2023 map — half a zone warmer, like about 56% of U.S. ZIP codes. The shift comes from a newer 1991–2020 averaging period plus more weather stations and better mapping; it does not mean last frost comes earlier. Why the 2023 map is warmer.
How does Evanston compare with Cicero, IL?
Both are in zone 6a. The typical last spring frost in Evanston (May 2) comes about 15 days later than in Cicero, IL (Apr 17), 14 miles away, and the first fall frost is Oct 14 versus Oct 26. The two cities use different NOAA stations.