Frost dates for 61311Ancona, IL
The average last spring frost in Ancona is April 12 and the average first fall frost is October 28, giving a typical growing season of about 199 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 12
- Average first fall frost
- Oct 28
- Growing season
- 199 days
Safer after Apr 25 (1-in-10 risk)
Possible by Oct 16 (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 9 · Apr 23 · May 8 | Oct 1 · Oct 18 · Oct 30 | 177 days | 100% |
| Frost / freeze (32°F) | Mar 30 · Apr 12 · Apr 25 | Oct 16 · Oct 28 · Nov 11 | 199 days | 100% |
| Hard freeze (28°F) | Mar 16 · Apr 1 · Apr 15 | Oct 27 · Nov 8 · Nov 25 | 222 days | 100% |
Planting calendar for Ancona
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 12 – May 18 |
| Tomatoes | Transplant outdoors | Apr 28 – Jul 8 |
| Peppers | Start seeds indoors | Mar 12 – Apr 12 |
| Peppers | Transplant outdoors | May 12 – Jun 12 |
| Eggplant | Start seeds indoors | Mar 29 – Apr 27 |
| Eggplant | Transplant outdoors | May 12 – Jun 12 |
| Cucumbers | Sow outdoors | May 12 – Jul 18 |
| Summer squash | Sow outdoors | Apr 28 – Jun 12 |
| Winter squash & pumpkins | Sow outdoors | May 12 – Jun 12 |
| Snap beans | Sow outdoors | Apr 28 – Aug 10 |
| Sweet corn | Sow outdoors | Apr 28 – Jul 8 |
| Watermelon & cantaloupe | Sow outdoors | May 12 – Jun 12 |
| Okra | Sow outdoors | May 5 – May 28 |
| Peas | Sow outdoors (spring) | Mar 12 – Apr 27 |
| Potatoes | Plant outdoors (spring) | Mar 12 – May 12 |
| Onions | Start seeds indoors (spring) | Jan 29 – Feb 25 |
| Onions | Transplant outdoors (spring) | Mar 29 – Apr 27 |
| Broccoli | Start seeds indoors (spring) | Feb 22 – Mar 28 |
| Broccoli | Transplant outdoors (spring) | Mar 29 – Apr 27 |
| Broccoli | Start seeds indoors (fall) | Jun 28 – Jul 8 |
| Broccoli | Transplant outdoors (fall) | Jul 28 – Aug 8 |
| Cabbage | Start seeds indoors (spring) | Feb 12 – Mar 12 |
| Cabbage | Transplant outdoors (spring) | Mar 12 – Apr 12 |
| Cabbage | Start seeds indoors (fall) | Jun 18 – Jul 18 |
| Cabbage | Transplant outdoors (fall) | Jul 18 – Aug 18 |
| Leaf lettuce | Sow outdoors (spring) | Mar 12 – May 28 |
| Leaf lettuce | Sow outdoors (fall) | Jul 18 – Sep 3 |
| Spinach | Sow outdoors (spring) | Mar 5 – Apr 18 |
| Spinach | Sow outdoors (fall) | Aug 4 – Sep 8 |
| Radishes | Sow outdoors (spring) | Mar 12 – May 2 |
| Radishes | Sow outdoors (fall) | Jul 18 – Sep 18 |
| Kale | Sow outdoors (spring) | Mar 29 – Apr 18 |
| Kale | Sow outdoors (fall) | Jul 11 – Aug 18 |
| Carrots | Sow outdoors (spring) | Apr 12 – May 28 |
| Carrots | Sow outdoors (fall) | Jun 18 – Aug 3 |
| Garlic | Plant outdoors (fall) | Oct 18 – Nov 18 |
Where these dates come from
ZIP code 61311 is matched to the NOAA station Streator 3 Se, IL, 6.7 km away, at 610 ft elevation (13 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Streator 3 Se, IL (used) | 610 ft | Apr 12 | Oct 28 |
| Minonk, IL | 750 ft | Apr 26 | Oct 17 |
| Pontiac, IL | 650 ft | Apr 16 | Oct 24 |
| Ottawa 5Sw, IL | 525 ft | Apr 20 | Oct 22 |
Frost dates near Ancona
- Long Point, IL 61333 · last Apr 26, first Oct 17
- Cornell, IL 61319 · last Apr 16, first Oct 24
- Streator, IL 61364 · last Apr 12, first Oct 28
- Dana, IL 61321 · last Apr 26, first Oct 17
- Wenona, IL 61377 · last Apr 26, first Oct 17
- Rutland, IL 61358 · last Apr 26, first Oct 17
- Flanagan, IL 61740 · last Apr 26, first Oct 17
- Blackstone, IL 61313 · last Apr 27, first Oct 15
Frequently asked questions
- When is the last frost in Ancona, IL?
- For ZIP code 61311, the average last spring frost (32°F) is April 12, based on NOAA 1991-2020 climate normals for the Streator 3 Se, IL weather station. There is a 1-in-10 chance of a frost after April 25.
- When is the first frost in Ancona, IL?
- The average first fall frost (32°F) is October 28. There is a 1-in-10 chance of frost by October 16, so tender plants are at risk from that point on.
- How long is the growing season in 61311?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 199 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.