Frost dates for 61411Adair, IL
The average last spring frost in Adair is April 17 and the average first fall frost is October 22, 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 22
- Growing season
- 185 days
Safer after May 2 (1-in-10 risk)
Possible by Oct 7 (1-in-10 risk)
Last frost typically in 165 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 15 · Apr 28 · May 12 | Sep 29 · Oct 12 · Oct 24 | 165 days | 100% |
| Frost / freeze (32°F) | Apr 4 · Apr 17 · May 2 | Oct 7 · Oct 22 · Nov 1 | 185 days | 100% |
| Hard freeze (28°F) | Mar 22 · Apr 7 · Apr 21 | Oct 18 · Oct 30 · Nov 13 | 204 days | 100% |
Planting calendar for Adair
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 – Jul 2 |
| 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 12 |
| Summer squash | Sow outdoors | May 3 – Jun 17 |
| Winter squash & pumpkins | Sow outdoors | May 17 – Jun 17 |
| Snap beans | Sow outdoors | May 3 – Aug 4 |
| Sweet corn | Sow outdoors | May 3 – Jul 2 |
| 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 22 – Jul 2 |
| Broccoli | Transplant outdoors (fall) | Jul 22 – Aug 2 |
| Cabbage | Start seeds indoors (spring) | Feb 17 – Mar 17 |
| Cabbage | Transplant outdoors (spring) | Mar 17 – Apr 17 |
| Cabbage | Start seeds indoors (fall) | Jun 12 – Jul 12 |
| Cabbage | Transplant outdoors (fall) | Jul 12 – Aug 12 |
| Leaf lettuce | Sow outdoors (spring) | Mar 17 – Jun 2 |
| Leaf lettuce | Sow outdoors (fall) | Jul 12 – Aug 28 |
| Spinach | Sow outdoors (spring) | Mar 10 – Apr 23 |
| Spinach | Sow outdoors (fall) | Jul 29 – Sep 2 |
| Radishes | Sow outdoors (spring) | Mar 17 – May 7 |
| Radishes | Sow outdoors (fall) | Jul 12 – Sep 12 |
| Kale | Sow outdoors (spring) | Apr 3 – Apr 23 |
| Kale | Sow outdoors (fall) | Jul 5 – Aug 12 |
| Carrots | Sow outdoors (spring) | Apr 17 – Jun 2 |
| Carrots | Sow outdoors (fall) | Jun 12 – Jul 28 |
| Garlic | Plant outdoors (fall) | Oct 12 – Nov 12 |
Where these dates come from
ZIP code 61411 is matched to the NOAA station Prairie City 2S, IL, 23.2 km away, at 650 ft elevation (0 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Prairie City 2S, IL (used) | 650 ft | Apr 17 | Oct 22 |
| Rushville, IL | 673 ft | Apr 16 | Oct 23 |
| Avon, IL | 640 ft | Apr 22 | Oct 19 |
| Havana, IL | 463 ft | Apr 17 | Oct 19 |
Frost dates near Adair
- Table Grove, IL 61482 · last Apr 17, first Oct 22
- Vermont, IL 61484 · last Apr 16, first Oct 23
- Industry, IL 61440 · last Apr 16, first Oct 23
- Bardolph, IL 61416 · last Apr 17, first Oct 22
- Marietta, IL 61459 · last Apr 17, first Oct 22
- Macomb, IL 61455 · last Apr 17, first Oct 22
- Ipava, IL 61441 · last Apr 17, first Oct 22
- Bushnell, IL 61422 · last Apr 17, first Oct 22
Frequently asked questions
- When is the last frost in Adair, IL?
- For ZIP code 61411, the average last spring frost (32°F) is April 17, based on NOAA 1991-2020 climate normals for the Prairie City 2S, IL weather station. There is a 1-in-10 chance of a frost after May 2.
- When is the first frost in Adair, IL?
- The average first fall frost (32°F) is October 22. There is a 1-in-10 chance of frost by October 7, so tender plants are at risk from that point on.
- How long is the growing season in 61411?
- 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.