Frost dates for 60501Summit Argo, IL
The average last spring frost in Summit Argo is April 11 and the average first fall frost is October 31, giving a typical growing season of about 201 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 11
- Average first fall frost
- Oct 31
- Growing season
- 201 days
Safer after Apr 27 (1-in-10 risk)
Possible by Oct 20 (1-in-10 risk)
First frost typically in 1 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 9 · Apr 23 · May 8 | Oct 8 · Oct 21 · Nov 1 | 180 days | 100% |
| Frost / freeze (32°F) | Mar 30 · Apr 11 · Apr 27 | Oct 20 · Oct 31 · Nov 14 | 201 days | 100% |
| Hard freeze (28°F) | Mar 15 · Apr 1 · Apr 14 | Oct 31 · Nov 11 · Nov 26 | 225 days | 100% |
Planting calendar for Summit Argo
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 11 – May 17 |
| Tomatoes | Transplant outdoors | Apr 27 – Jul 11 |
| Peppers | Start seeds indoors | Mar 11 – Apr 11 |
| Peppers | Transplant outdoors | May 11 – Jun 11 |
| Eggplant | Start seeds indoors | Mar 28 – Apr 26 |
| Eggplant | Transplant outdoors | May 11 – Jun 11 |
| Cucumbers | Sow outdoors | May 11 – Jul 21 |
| Summer squash | Sow outdoors | Apr 27 – Jun 11 |
| Winter squash & pumpkins | Sow outdoors | May 11 – Jun 11 |
| Snap beans | Sow outdoors | Apr 27 – Aug 13 |
| Sweet corn | Sow outdoors | Apr 27 – Jul 11 |
| Watermelon & cantaloupe | Sow outdoors | May 11 – Jun 11 |
| Okra | Sow outdoors | May 4 – May 27 |
| Peas | Sow outdoors (spring) | Mar 11 – Apr 26 |
| Potatoes | Plant outdoors (spring) | Mar 11 – May 11 |
| Onions | Start seeds indoors (spring) | Jan 28 – Feb 24 |
| Onions | Transplant outdoors (spring) | Mar 28 – Apr 26 |
| Broccoli | Start seeds indoors (spring) | Feb 21 – Mar 27 |
| Broccoli | Transplant outdoors (spring) | Mar 28 – Apr 26 |
| Broccoli | Start seeds indoors (fall) | Jul 1 – Jul 11 |
| Broccoli | Transplant outdoors (fall) | Jul 31 – Aug 11 |
| Cabbage | Start seeds indoors (spring) | Feb 11 – Mar 11 |
| Cabbage | Transplant outdoors (spring) | Mar 11 – Apr 11 |
| Cabbage | Start seeds indoors (fall) | Jun 21 – Jul 21 |
| Cabbage | Transplant outdoors (fall) | Jul 21 – Aug 21 |
| Leaf lettuce | Sow outdoors (spring) | Mar 11 – May 27 |
| Leaf lettuce | Sow outdoors (fall) | Jul 21 – Sep 6 |
| Spinach | Sow outdoors (spring) | Mar 4 – Apr 17 |
| Spinach | Sow outdoors (fall) | Aug 7 – Sep 11 |
| Radishes | Sow outdoors (spring) | Mar 11 – May 1 |
| Radishes | Sow outdoors (fall) | Jul 21 – Sep 21 |
| Kale | Sow outdoors (spring) | Mar 28 – Apr 17 |
| Kale | Sow outdoors (fall) | Jul 14 – Aug 21 |
| Carrots | Sow outdoors (spring) | Apr 11 – May 27 |
| Carrots | Sow outdoors (fall) | Jun 21 – Aug 6 |
| Garlic | Plant outdoors (fall) | Oct 21 – Nov 21 |
Where these dates come from
ZIP code 60501 is matched to the NOAA station Chicago Midway Ap, IL, 6 km away, at 612 ft elevation (11 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Chicago Midway Ap, IL (used) | 612 ft | Apr 11 | Oct 31 |
| Chicago Midway Ap 3Sw, IL | 620 ft | Apr 10 | Nov 1 |
| Little Red School Hse, IL | 715 ft | Apr 19 | Oct 22 |
| Chicago Northerly Is, IL | 583 ft | Apr 10 | Nov 5 |
Frost dates near Summit Argo
- Lyons, IL 60534 · last Apr 11, first Oct 31
- La Grange, IL 60525 · last Apr 10, first Nov 1
- Justice, IL 60458 · last Apr 10, first Nov 1
- Bridgeview, IL 60455 · last Apr 10, first Nov 1
- Chicago, IL 60638 · last Apr 11, first Oct 31
- Brookfield, IL 60513 · last Apr 11, first Oct 31
- Burbank, IL 60459 · last Apr 10, first Nov 1
- Hickory Hills, IL 60457 · last Apr 10, first Nov 1
Frequently asked questions
- When is the last frost in Summit Argo, IL?
- For ZIP code 60501, the average last spring frost (32°F) is April 11, based on NOAA 1991-2020 climate normals for the Chicago Midway Ap, IL weather station. There is a 1-in-10 chance of a frost after April 27.
- When is the first frost in Summit Argo, IL?
- The average first fall frost (32°F) is October 31. There is a 1-in-10 chance of frost by October 20, so tender plants are at risk from that point on.
- How long is the growing season in 60501?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 201 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.