Frost dates for 62840Frankfort Heights, IL
The average last spring frost in Frankfort Heights is April 4 and the average first fall frost is October 28, giving a typical growing season of about 206 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 4
- Average first fall frost
- Oct 28
- Growing season
- 206 days
Safer after Apr 21 (1-in-10 risk)
Possible by Oct 15 (1-in-10 risk)
Last frost typically in 153 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 2 · Apr 18 · May 4 | Oct 5 · Oct 18 · Oct 29 | 182 days | 100% |
| Frost / freeze (32°F) | Mar 19 · Apr 4 · Apr 21 | Oct 15 · Oct 28 · Nov 10 | 206 days | 100% |
| Hard freeze (28°F) | Mar 6 · Mar 25 · Apr 10 | Oct 26 · Nov 7 · Nov 26 | 229 days | 100% |
Planting calendar for Frankfort Heights
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 4 – May 10 |
| Tomatoes | Transplant outdoors | Apr 20 – Jul 8 |
| Peppers | Start seeds indoors | Mar 4 – Apr 4 |
| Peppers | Transplant outdoors | May 4 – Jun 4 |
| Eggplant | Start seeds indoors | Mar 21 – Apr 19 |
| Eggplant | Transplant outdoors | May 4 – Jun 4 |
| Cucumbers | Sow outdoors | May 4 – Jul 18 |
| Summer squash | Sow outdoors | Apr 20 – Jun 4 |
| Winter squash & pumpkins | Sow outdoors | May 4 – Jun 4 |
| Snap beans | Sow outdoors | Apr 20 – Aug 10 |
| Sweet corn | Sow outdoors | Apr 20 – Jul 8 |
| Watermelon & cantaloupe | Sow outdoors | May 4 – Jun 4 |
| Okra | Sow outdoors | Apr 27 – May 20 |
| Peas | Sow outdoors (spring) | Mar 4 – Apr 19 |
| Potatoes | Plant outdoors (spring) | Mar 4 – May 4 |
| Onions | Start seeds indoors (spring) | Jan 21 – Feb 17 |
| Onions | Transplant outdoors (spring) | Mar 21 – Apr 19 |
| Broccoli | Start seeds indoors (spring) | Feb 14 – Mar 20 |
| Broccoli | Transplant outdoors (spring) | Mar 21 – Apr 19 |
| Broccoli | Start seeds indoors (fall) | Jun 28 – Jul 8 |
| Broccoli | Transplant outdoors (fall) | Jul 28 – Aug 8 |
| Cabbage | Start seeds indoors (spring) | Feb 4 – Mar 4 |
| Cabbage | Transplant outdoors (spring) | Mar 4 – Apr 4 |
| Cabbage | Start seeds indoors (fall) | Jun 18 – Jul 18 |
| Cabbage | Transplant outdoors (fall) | Jul 18 – Aug 18 |
| Leaf lettuce | Sow outdoors (spring) | Mar 4 – May 20 |
| Leaf lettuce | Sow outdoors (fall) | Jul 18 – Sep 3 |
| Spinach | Sow outdoors (spring) | Feb 25 – Apr 10 |
| Spinach | Sow outdoors (fall) | Aug 4 – Sep 8 |
| Radishes | Sow outdoors (spring) | Mar 4 – Apr 24 |
| Radishes | Sow outdoors (fall) | Jul 18 – Sep 18 |
| Kale | Sow outdoors (spring) | Mar 21 – Apr 10 |
| Kale | Sow outdoors (fall) | Jul 11 – Aug 18 |
| Carrots | Sow outdoors (spring) | Apr 4 – May 20 |
| Carrots | Sow outdoors (fall) | Jun 18 – Aug 3 |
| Garlic | Plant outdoors (fall) | Oct 18 – Nov 18 |
Where these dates come from
ZIP code 62840 is matched to the NOAA station Benton 2 N, IL, 4.8 km away, at 445 ft elevation (5 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Benton 2 N, IL (used) | 445 ft | Apr 4 | Oct 28 |
| Rend Lake Dam, IL | 455 ft | Apr 4 | Oct 27 |
| Du Quoin 4 Se, IL | 420 ft | Apr 6 | Oct 22 |
| Carbondale Sewage Plt, IL | 390 ft | Apr 9 | Oct 22 |
Frost dates near Frankfort Heights
- Benton, IL 62812 · last Apr 4, first Oct 28
- Buckner, IL 62819 · last Apr 4, first Oct 28
- Valier, IL 62891 · last Apr 4, first Oct 28
- Orient, IL 62874 · last Apr 4, first Oct 28
- Logan, IL 62856 · last Apr 4, first Oct 28
- Christopher, IL 62822 · last Apr 6, first Oct 22
- West Frankfort, IL 62896 · last Apr 4, first Oct 28
- Whittington, IL 62897 · last Apr 4, first Oct 28
Frequently asked questions
- When is the last frost in Frankfort Heights, IL?
- For ZIP code 62840, the average last spring frost (32°F) is April 4, based on NOAA 1991-2020 climate normals for the Benton 2 N, IL weather station. There is a 1-in-10 chance of a frost after April 21.
- When is the first frost in Frankfort Heights, IL?
- The average first fall frost (32°F) is October 28. There is a 1-in-10 chance of frost by October 15, so tender plants are at risk from that point on.
- How long is the growing season in 62840?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 206 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.