Frost dates for 62239Dupo, IL
The average last spring frost in Dupo is April 6 and the average first fall frost is October 27, giving a typical growing season of about 203 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 6
- Average first fall frost
- Oct 27
- Growing season
- 203 days
Safer after Apr 20 (1-in-10 risk)
Possible by Oct 14 (1-in-10 risk)
Last frost typically in 156 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 4 · Apr 18 · May 3 | Oct 5 · Oct 18 · Oct 28 | 181 days | 100% |
| Frost / freeze (32°F) | Mar 22 · Apr 6 · Apr 20 | Oct 14 · Oct 27 · Nov 7 | 203 days | 100% |
| Hard freeze (28°F) | Mar 11 · Mar 27 · Apr 10 | Oct 25 · Nov 5 · Nov 23 | 225 days | 100% |
Planting calendar for Dupo
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 6 – May 12 |
| Tomatoes | Transplant outdoors | Apr 22 – Jul 7 |
| Peppers | Start seeds indoors | Mar 6 – Apr 6 |
| Peppers | Transplant outdoors | May 6 – Jun 6 |
| Eggplant | Start seeds indoors | Mar 23 – Apr 21 |
| Eggplant | Transplant outdoors | May 6 – Jun 6 |
| Cucumbers | Sow outdoors | May 6 – Jul 17 |
| Summer squash | Sow outdoors | Apr 22 – Jun 6 |
| Winter squash & pumpkins | Sow outdoors | May 6 – Jun 6 |
| Snap beans | Sow outdoors | Apr 22 – Aug 9 |
| Sweet corn | Sow outdoors | Apr 22 – Jul 7 |
| Watermelon & cantaloupe | Sow outdoors | May 6 – Jun 6 |
| Okra | Sow outdoors | Apr 29 – May 22 |
| Peas | Sow outdoors (spring) | Mar 6 – Apr 21 |
| Potatoes | Plant outdoors (spring) | Mar 6 – May 6 |
| Onions | Start seeds indoors (spring) | Jan 23 – Feb 19 |
| Onions | Transplant outdoors (spring) | Mar 23 – Apr 21 |
| Broccoli | Start seeds indoors (spring) | Feb 16 – Mar 22 |
| Broccoli | Transplant outdoors (spring) | Mar 23 – Apr 21 |
| Broccoli | Start seeds indoors (fall) | Jun 27 – Jul 7 |
| Broccoli | Transplant outdoors (fall) | Jul 27 – Aug 7 |
| Cabbage | Start seeds indoors (spring) | Feb 6 – Mar 6 |
| Cabbage | Transplant outdoors (spring) | Mar 6 – Apr 6 |
| Cabbage | Start seeds indoors (fall) | Jun 17 – Jul 17 |
| Cabbage | Transplant outdoors (fall) | Jul 17 – Aug 17 |
| Leaf lettuce | Sow outdoors (spring) | Mar 6 – May 22 |
| Leaf lettuce | Sow outdoors (fall) | Jul 17 – Sep 2 |
| Spinach | Sow outdoors (spring) | Feb 27 – Apr 12 |
| Spinach | Sow outdoors (fall) | Aug 3 – Sep 7 |
| Radishes | Sow outdoors (spring) | Mar 6 – Apr 26 |
| Radishes | Sow outdoors (fall) | Jul 17 – Sep 17 |
| Kale | Sow outdoors (spring) | Mar 23 – Apr 12 |
| Kale | Sow outdoors (fall) | Jul 10 – Aug 17 |
| Carrots | Sow outdoors (spring) | Apr 6 – May 22 |
| Carrots | Sow outdoors (fall) | Jun 17 – Aug 2 |
| Garlic | Plant outdoors (fall) | Oct 17 – Nov 17 |
Where these dates come from
ZIP code 62239 is matched to the NOAA station Cahokia, IL, 5.8 km away, at 400 ft elevation (17 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Cahokia, IL (used) | 400 ft | Apr 6 | Oct 27 |
| Cahokia St Louis Ap, IL | 413 ft | Apr 8 | Oct 26 |
| St Louis Sci Ctr, MO | 515 ft | Apr 1 | Nov 4 |
| St Louis Lambert Intl Ap, MO | 531 ft | Apr 2 | Nov 4 |
Frost dates near Dupo
- East Carondelet, IL 62240 · last Apr 6, first Oct 27
- Saint Louis, MO 63111 · last Apr 6, first Oct 27
- East Saint Louis, IL 62206 · last Apr 8, first Oct 26
- Columbia, IL 62236 · last Apr 6, first Oct 27
- Millstadt, IL 62260 · last Apr 8, first Oct 26
- Belleville, IL 62223 · last Apr 8, first Oct 26
- National Stock Yards, IL 62071 · last Apr 8, first Oct 26
- Venice, IL 62090 · last Apr 8, first Oct 26
Frequently asked questions
- When is the last frost in Dupo, IL?
- For ZIP code 62239, the average last spring frost (32°F) is April 6, based on NOAA 1991-2020 climate normals for the Cahokia, IL weather station. There is a 1-in-10 chance of a frost after April 20.
- When is the first frost in Dupo, IL?
- The average first fall frost (32°F) is October 27. There is a 1-in-10 chance of frost by October 14, so tender plants are at risk from that point on.
- How long is the growing season in 62239?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 203 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.