Springfield, Illinois: planting zone & frost dates
Springfield 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 20 and the first fall frost around Oct 17.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | Apr 30 | Oct 9 |
| Typical planning date (30% risk) | Apr 20 | Oct 17 |
| Median (50%) | Apr 15 | Oct 22 |
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 SPRINGFIELD #2, IL (USC00118186), 1.7 mi (2.8 km) from the city center and about the same elevation as the city center (-0 m). Record used for the 1991–2020 normals: 12 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Springfield
All 9 ZIP codes covering Springfield are in zone 6a.
Vegetable planting calendar for Springfield
Dates are counted from the 30%-risk frost dates above (last frost Apr 20, first frost Oct 17). 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 23 – Mar 9 | Apr 27 – May 11 | — | — |
| Pepper | Feb 9 – Feb 23 | May 4 – May 18 | — | — |
| Lettuce | Mar 9 – Mar 23 | Apr 6 – Apr 27 | Mar 23 – May 4 | Aug 8 – Sep 5 |
| Green Beans | — | — | Apr 27 – Jun 1 | Jul 25 – Aug 8 |
| Sweet Corn | — | — | Apr 27 – May 25 | — |
| Zucchini & Summer Squash | Mar 23 – Mar 30 | Apr 27 – May 11 | Apr 27 – May 18 | Jul 25 – Aug 8 |
| Cucumber | Mar 23 – Mar 30 | May 4 – May 11 | Apr 27 – May 18 | Jul 25 – Aug 8 |
| Carrot | — | — | Mar 30 – May 4 | Jul 25 – Aug 8 |
| Onion | Jan 26 – Feb 9 | Mar 23 – Apr 6 | — | — |
| Potato | — | Mar 23 – Apr 13 | — | — |
| Basil | Mar 9 – Mar 23 | May 4 – May 18 | May 4 – May 25 | — |
| Spinach | — | — | Mar 9 – Apr 6 | Aug 22 – Sep 19 |
| Kale | Feb 23 – Mar 9 | Mar 23 – Apr 13 | Mar 23 – Apr 13 | Aug 8 – Sep 5 |
| Broccoli | Feb 23 – Mar 9 | Apr 6 – Apr 27 | — | Jul 25 – Aug 8 |
| Peas | — | — | Mar 9 – Mar 30 | Aug 8 – Aug 22 |
| Eggplant | Feb 9 – Feb 23 | May 4 – May 18 | — | — |
| Cabbage | Feb 23 – Mar 9 | Mar 23 – Apr 6 | — | Jul 25 – Aug 8 |
| Radish | — | — | Mar 16 – May 4 | Sep 5 – Oct 3 |
| Strawberry | — | Mar 23 – Apr 13 | — | — |
| Beets | — | — | Mar 30 – May 11 | Aug 8 – Aug 22 |
Nearby cities in Illinois
- Peoria — zone 6a, last frost Apr 23, first frost Oct 18
- Bloomington — zone 6a, last frost May 1, first frost Oct 11
- Champaign — zone 6a, last frost Apr 21, first frost Oct 19
- Joliet — zone 6a, last frost Apr 26, first frost Oct 20
- Aurora — zone 5b, last frost Apr 25, first frost Oct 18
- Naperville — zone 5b, last frost May 4, first frost Oct 11
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
Springfield gardening questions
When is the last frost in Springfield, IL?
Plan around Apr 20. At NOAA's Springfield #2, IL station, 1.7 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 15, and after Apr 30 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Apr 5. The last frost is fairly predictable here: only 27 days separate the 90% and 10% dates (median for cities on this site: 36 days).
When should I plant tomatoes in Springfield, IL?
Start seeds indoors Feb 23 – Mar 9 and set transplants outside Apr 27 – May 11, once nights stay above 50°F and the soil is near 60°F. That leaves 180 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 Springfield?
About 188 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 169 days, and in 1 year in 10 it runs 206 days or more. In fall there is a 10% chance of frost by Oct 9 and a 30% chance by Oct 17. That ranks 6th longest of 14 Illinois cities on this site.
When should I plant a fall garden in Springfield?
Count back from the first fall frost (Oct 17): transplant broccoli Jul 25 – Aug 8; sow kale Aug 8 – Sep 5; sow lettuce Aug 8 – Sep 5; sow radishes Sep 5 – Oct 3. 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 Springfield's hardiness zone change on the 2023 map?
No. Going by the zone that covers most of the city's land, Springfield is zone 6a on both the 2012 and the 2023 USDA maps (PRISM/OSU ZIP listings). About 42% of U.S. ZIP codes kept their half-zone in 2023. Why the 2023 map is warmer.
How does Springfield compare with Bloomington, IL?
Both are in zone 6a. The typical last spring frost in Springfield (Apr 20) comes about 11 days earlier than in Bloomington, IL (May 1), 59 miles away, and the first fall frost is Oct 17 versus Oct 11. Springfield sits about 242 ft lower, which explains part of the gap. The two cities use different NOAA stations.