Frost dates for 63341Defiance, MO
The average last spring frost in Defiance is April 10 and the average first fall frost is October 26, giving a typical growing season of about 199 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 10
- Average first fall frost
- Oct 26
- Growing season
- 199 days
Safer after Apr 26 (1-in-10 risk)
Possible by Oct 12 (1-in-10 risk)
Last frost typically in 159 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 8 · Apr 22 · May 6 | Oct 1 · Oct 16 · Oct 28 | 176 days | 100% |
| Frost / freeze (32°F) | Mar 26 · Apr 10 · Apr 26 | Oct 12 · Oct 26 · Nov 8 | 199 days | 100% |
| Hard freeze (28°F) | Mar 12 · Mar 31 · Apr 15 | Oct 22 · Nov 5 · Nov 22 | 221 days | 100% |
Planting calendar for Defiance
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 10 – May 16 |
| Tomatoes | Transplant outdoors | Apr 26 – Jul 6 |
| Peppers | Start seeds indoors | Mar 10 – Apr 10 |
| Peppers | Transplant outdoors | May 10 – Jun 10 |
| Eggplant | Start seeds indoors | Mar 27 – Apr 25 |
| Eggplant | Transplant outdoors | May 10 – Jun 10 |
| Cucumbers | Sow outdoors | May 10 – Jul 16 |
| Summer squash | Sow outdoors | Apr 26 – Jun 10 |
| Winter squash & pumpkins | Sow outdoors | May 10 – Jun 10 |
| Snap beans | Sow outdoors | Apr 26 – Aug 8 |
| Sweet corn | Sow outdoors | Apr 26 – Jul 6 |
| Watermelon & cantaloupe | Sow outdoors | May 10 – Jun 10 |
| Okra | Sow outdoors | May 3 – May 26 |
| Peas | Sow outdoors (spring) | Mar 10 – Apr 25 |
| Potatoes | Plant outdoors (spring) | Mar 10 – May 10 |
| Onions | Start seeds indoors (spring) | Jan 27 – Feb 23 |
| Onions | Transplant outdoors (spring) | Mar 27 – Apr 25 |
| Broccoli | Start seeds indoors (spring) | Feb 20 – Mar 26 |
| Broccoli | Transplant outdoors (spring) | Mar 27 – Apr 25 |
| Broccoli | Start seeds indoors (fall) | Jun 26 – Jul 6 |
| Broccoli | Transplant outdoors (fall) | Jul 26 – Aug 6 |
| Cabbage | Start seeds indoors (spring) | Feb 10 – Mar 10 |
| Cabbage | Transplant outdoors (spring) | Mar 10 – Apr 10 |
| Cabbage | Start seeds indoors (fall) | Jun 16 – Jul 16 |
| Cabbage | Transplant outdoors (fall) | Jul 16 – Aug 16 |
| Leaf lettuce | Sow outdoors (spring) | Mar 10 – May 26 |
| Leaf lettuce | Sow outdoors (fall) | Jul 16 – Sep 1 |
| Spinach | Sow outdoors (spring) | Mar 3 – Apr 16 |
| Spinach | Sow outdoors (fall) | Aug 2 – Sep 6 |
| Radishes | Sow outdoors (spring) | Mar 10 – Apr 30 |
| Radishes | Sow outdoors (fall) | Jul 16 – Sep 16 |
| Kale | Sow outdoors (spring) | Mar 27 – Apr 16 |
| Kale | Sow outdoors (fall) | Jul 9 – Aug 16 |
| Carrots | Sow outdoors (spring) | Apr 10 – May 26 |
| Carrots | Sow outdoors (fall) | Jun 16 – Aug 1 |
| Garlic | Plant outdoors (fall) | Oct 16 – Nov 16 |
Where these dates come from
ZIP code 63341 is matched to the NOAA station Weldon Spring Nws, MO, 13.5 km away, at 610 ft elevation (3 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Weldon Spring Nws, MO (used) | 610 ft | Apr 10 | Oct 26 |
| St Louis Sprt Of S L Ap, MO | 462 ft | Apr 12 | Oct 23 |
| Washington, MO | 487 ft | Apr 8 | Oct 25 |
| St Peters 2 Se, MO | 575 ft | Apr 9 | Oct 26 |
Frost dates near Defiance
- New Melle, MO 63365 · last Apr 10, first Oct 26
- Saint Albans, MO 63073 · last Apr 12, first Oct 23
- Augusta, MO 63332 · last Apr 11, first Oct 23
- O Fallon, MO 63368 · last Apr 10, first Oct 26
- Foristell, MO 63348 · last Apr 14, first Oct 23
- Lake Saint Louis, MO 63367 · last Apr 10, first Oct 26
- Dutzow, MO 63342 · last Apr 11, first Oct 23
- Wentzville, MO 63385 · last Apr 10, first Oct 26
Frequently asked questions
- When is the last frost in Defiance, MO?
- For ZIP code 63341, the average last spring frost (32°F) is April 10, based on NOAA 1991-2020 climate normals for the Weldon Spring Nws, MO weather station. There is a 1-in-10 chance of a frost after April 26.
- When is the first frost in Defiance, MO?
- The average first fall frost (32°F) is October 26. There is a 1-in-10 chance of frost by October 12, so tender plants are at risk from that point on.
- How long is the growing season in 63341?
- 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.