Frost dates for 61532Forest City, IL
The average last spring frost in Forest City is April 17 and the average first fall frost is October 19, giving a typical growing season of about 185 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 17
- Average first fall frost
- Oct 19
- Growing season
- 185 days
Safer after May 3 (1-in-10 risk)
Possible by Oct 1 (1-in-10 risk)
Last frost typically in 169 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | Apr 13 · Apr 26 · May 11 | Sep 24 · Oct 8 · Oct 21 | 163 days | 100% |
| Frost / freeze (32°F) | Apr 2 · Apr 17 · May 3 | Oct 1 · Oct 19 · Oct 31 | 185 days | 100% |
| Hard freeze (28°F) | Mar 22 · Apr 5 · Apr 21 | Oct 15 · Oct 29 · Nov 13 | 204 days | 100% |
Planting calendar for Forest City
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Mar 17 – May 23 |
| Tomatoes | Transplant outdoors | May 3 – Jun 29 |
| Peppers | Start seeds indoors | Mar 17 – Apr 17 |
| Peppers | Transplant outdoors | May 17 – Jun 17 |
| Eggplant | Start seeds indoors | Apr 3 – May 2 |
| Eggplant | Transplant outdoors | May 17 – Jun 17 |
| Cucumbers | Sow outdoors | May 17 – Jul 9 |
| Summer squash | Sow outdoors | May 3 – Jun 17 |
| Winter squash & pumpkins | Sow outdoors | May 17 – Jun 17 |
| Snap beans | Sow outdoors | May 3 – Aug 1 |
| Sweet corn | Sow outdoors | May 3 – Jun 29 |
| Watermelon & cantaloupe | Sow outdoors | May 17 – Jun 17 |
| Okra | Sow outdoors | May 10 – Jun 2 |
| Peas | Sow outdoors (spring) | Mar 17 – May 2 |
| Potatoes | Plant outdoors (spring) | Mar 17 – May 17 |
| Onions | Start seeds indoors (spring) | Feb 3 – Mar 2 |
| Onions | Transplant outdoors (spring) | Apr 3 – May 2 |
| Broccoli | Start seeds indoors (spring) | Feb 27 – Apr 2 |
| Broccoli | Transplant outdoors (spring) | Apr 3 – May 2 |
| Broccoli | Start seeds indoors (fall) | Jun 19 – Jun 29 |
| Broccoli | Transplant outdoors (fall) | Jul 19 – Jul 30 |
| Cabbage | Start seeds indoors (spring) | Feb 17 – Mar 17 |
| Cabbage | Transplant outdoors (spring) | Mar 17 – Apr 17 |
| Cabbage | Start seeds indoors (fall) | Jun 9 – Jul 9 |
| Cabbage | Transplant outdoors (fall) | Jul 9 – Aug 9 |
| Leaf lettuce | Sow outdoors (spring) | Mar 17 – Jun 2 |
| Leaf lettuce | Sow outdoors (fall) | Jul 9 – Aug 25 |
| Spinach | Sow outdoors (spring) | Mar 10 – Apr 23 |
| Spinach | Sow outdoors (fall) | Jul 26 – Aug 30 |
| Radishes | Sow outdoors (spring) | Mar 17 – May 7 |
| Radishes | Sow outdoors (fall) | Jul 9 – Sep 9 |
| Kale | Sow outdoors (spring) | Apr 3 – Apr 23 |
| Kale | Sow outdoors (fall) | Jul 2 – Aug 9 |
| Carrots | Sow outdoors (spring) | Apr 17 – Jun 2 |
| Carrots | Sow outdoors (fall) | Jun 9 – Jul 25 |
| Garlic | Plant outdoors (fall) | Oct 9 – Nov 9 |
Where these dates come from
ZIP code 61532 is matched to the NOAA station Havana, IL, 20.6 km away, at 463 ft elevation (23 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Havana, IL (used) | 463 ft | Apr 17 | Oct 19 |
| Mason City 4Se, IL | 600 ft | Apr 17 | Oct 18 |
| Peoria Gtr Peoria Ap, IL | 650 ft | Apr 16 | Oct 23 |
| Petersburg 1E, IL | 600 ft | Apr 13 | Oct 21 |
Frost dates near Forest City
- Manito, IL 61546 · last Apr 16, first Oct 23
- Topeka, IL 61567 · last Apr 17, first Oct 19
- San Jose, IL 62682 · last Apr 17, first Oct 18
- Liverpool, IL 61543 · last Apr 17, first Oct 19
- Easton, IL 62633 · last Apr 17, first Oct 19
- Green Valley, IL 61534 · last Apr 16, first Oct 23
- Havana, IL 62644 · last Apr 17, first Oct 19
- Mason City, IL 62664 · last Apr 17, first Oct 18
Frequently asked questions
- When is the last frost in Forest City, IL?
- For ZIP code 61532, the average last spring frost (32°F) is April 17, based on NOAA 1991-2020 climate normals for the Havana, IL weather station. There is a 1-in-10 chance of a frost after May 3.
- When is the first frost in Forest City, IL?
- The average first fall frost (32°F) is October 19. There is a 1-in-10 chance of frost by October 1, so tender plants are at risk from that point on.
- How long is the growing season in 61532?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 185 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.