Frost dates for 62346La Prairie, IL
The average last spring frost in La Prairie is April 18 and the average first fall frost is October 21, giving a typical growing season of about 187 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 18
- Average first fall frost
- Oct 21
- Growing season
- 187 days
Safer after May 1 (1-in-10 risk)
Possible by Oct 6 (1-in-10 risk)
Last frost typically in 170 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 28 · May 11 | Sep 25 · Oct 11 · Oct 23 | 166 days | 100% |
| Frost / freeze (32°F) | Apr 3 · Apr 18 · May 1 | Oct 6 · Oct 21 · Nov 1 | 187 days | 100% |
| Hard freeze (28°F) | Mar 21 · Apr 7 · Apr 21 | Oct 19 · Oct 31 · Nov 14 | 207 days | 100% |
Planting calendar for La Prairie
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 18 – May 24 |
| Tomatoes | Transplant outdoors | May 4 – Jul 1 |
| Peppers | Start seeds indoors | Mar 18 – Apr 18 |
| Peppers | Transplant outdoors | May 18 – Jun 18 |
| Eggplant | Start seeds indoors | Apr 4 – May 3 |
| Eggplant | Transplant outdoors | May 18 – Jun 18 |
| Cucumbers | Sow outdoors | May 18 – Jul 11 |
| Summer squash | Sow outdoors | May 4 – Jun 18 |
| Winter squash & pumpkins | Sow outdoors | May 18 – Jun 18 |
| Snap beans | Sow outdoors | May 4 – Aug 3 |
| Sweet corn | Sow outdoors | May 4 – Jul 1 |
| Watermelon & cantaloupe | Sow outdoors | May 18 – Jun 18 |
| Okra | Sow outdoors | May 11 – Jun 3 |
| Peas | Sow outdoors (spring) | Mar 18 – May 3 |
| Potatoes | Plant outdoors (spring) | Mar 18 – May 18 |
| Onions | Start seeds indoors (spring) | Feb 4 – Mar 3 |
| Onions | Transplant outdoors (spring) | Apr 4 – May 3 |
| Broccoli | Start seeds indoors (spring) | Feb 28 – Apr 3 |
| Broccoli | Transplant outdoors (spring) | Apr 4 – May 3 |
| Broccoli | Start seeds indoors (fall) | Jun 21 – Jul 1 |
| Broccoli | Transplant outdoors (fall) | Jul 21 – Aug 1 |
| Cabbage | Start seeds indoors (spring) | Feb 18 – Mar 18 |
| Cabbage | Transplant outdoors (spring) | Mar 18 – Apr 18 |
| Cabbage | Start seeds indoors (fall) | Jun 11 – Jul 11 |
| Cabbage | Transplant outdoors (fall) | Jul 11 – Aug 11 |
| Leaf lettuce | Sow outdoors (spring) | Mar 18 – Jun 3 |
| Leaf lettuce | Sow outdoors (fall) | Jul 11 – Aug 27 |
| Spinach | Sow outdoors (spring) | Mar 11 – Apr 24 |
| Spinach | Sow outdoors (fall) | Jul 28 – Sep 1 |
| Radishes | Sow outdoors (spring) | Mar 18 – May 8 |
| Radishes | Sow outdoors (fall) | Jul 11 – Sep 11 |
| Kale | Sow outdoors (spring) | Apr 4 – Apr 24 |
| Kale | Sow outdoors (fall) | Jul 4 – Aug 11 |
| Carrots | Sow outdoors (spring) | Apr 18 – Jun 3 |
| Carrots | Sow outdoors (fall) | Jun 11 – Jul 27 |
| Garlic | Plant outdoors (fall) | Oct 11 – Nov 11 |
Where these dates come from
ZIP code 62346 is matched to the NOAA station Golden, IL, 6.5 km away, at 718 ft elevation (19 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Golden, IL (used) | 718 ft | Apr 18 | Oct 21 |
| Bentley, IL | 650 ft | Apr 13 | Oct 22 |
| Quincy Rgnl Ap, IL | 769 ft | Apr 14 | Oct 23 |
| Rushville, IL | 673 ft | Apr 16 | Oct 23 |
Frost dates near La Prairie
- Golden, IL 62339 · last Apr 18, first Oct 21
- Augusta, IL 62311 · last Apr 13, first Oct 22
- Huntsville, IL 62344 · last Apr 16, first Oct 23
- Bowen, IL 62316 · last Apr 13, first Oct 22
- Clayton, IL 62324 · last Apr 14, first Oct 23
- Camp Point, IL 62320 · last Apr 14, first Oct 23
- Plymouth, IL 62367 · last Apr 13, first Oct 22
- Timewell, IL 62375 · last Apr 18, first Oct 15
Frequently asked questions
- When is the last frost in La Prairie, IL?
- For ZIP code 62346, the average last spring frost (32°F) is April 18, based on NOAA 1991-2020 climate normals for the Golden, IL weather station. There is a 1-in-10 chance of a frost after May 1.
- When is the first frost in La Prairie, IL?
- The average first fall frost (32°F) is October 21. There is a 1-in-10 chance of frost by October 6, so tender plants are at risk from that point on.
- How long is the growing season in 62346?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 187 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.