Frost dates for 63151Saint Louis, MO
The average last spring frost in Saint Louis is April 2 and the average first fall frost is November 4, giving a typical growing season of about 215 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 2
- Average first fall frost
- Nov 4
- Growing season
- 215 days
Safer after Apr 17 (1-in-10 risk)
Possible by Oct 23 (1-in-10 risk)
First frost typically in 4 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) | Mar 31 · Apr 13 · Apr 28 | Oct 14 · Oct 26 · Nov 6 | 195 days | 100% |
| Frost / freeze (32°F) | Mar 17 · Apr 2 · Apr 17 | Oct 23 · Nov 4 · Nov 18 | 215 days | 100% |
| Hard freeze (28°F) | Mar 5 · Mar 23 · Apr 7 | Nov 2 · Nov 13 · Nov 30 | 236 days | 100% |
Planting calendar for Saint Louis
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 2 – May 8 |
| Tomatoes | Transplant outdoors | Apr 18 – Jul 15 |
| Peppers | Start seeds indoors | Mar 2 – Apr 2 |
| Peppers | Transplant outdoors | May 2 – Jun 2 |
| Eggplant | Start seeds indoors | Mar 19 – Apr 17 |
| Eggplant | Transplant outdoors | May 2 – Jun 2 |
| Cucumbers | Sow outdoors | May 2 – Jul 25 |
| Summer squash | Sow outdoors | Apr 18 – Jun 2 |
| Winter squash & pumpkins | Sow outdoors | May 2 – Jun 2 |
| Snap beans | Sow outdoors | Apr 18 – Aug 17 |
| Sweet corn | Sow outdoors | Apr 18 – Jul 15 |
| Watermelon & cantaloupe | Sow outdoors | May 2 – Jun 2 |
| Okra | Sow outdoors | Apr 25 – May 18 |
| Peas | Sow outdoors (spring) | Mar 2 – Apr 17 |
| Potatoes | Plant outdoors (spring) | Mar 2 – May 2 |
| Onions | Start seeds indoors (spring) | Jan 19 – Feb 15 |
| Onions | Transplant outdoors (spring) | Mar 19 – Apr 17 |
| Broccoli | Start seeds indoors (spring) | Feb 12 – Mar 18 |
| Broccoli | Transplant outdoors (spring) | Mar 19 – Apr 17 |
| Broccoli | Start seeds indoors (fall) | Jul 5 – Jul 15 |
| Broccoli | Transplant outdoors (fall) | Aug 4 – Aug 15 |
| Cabbage | Start seeds indoors (spring) | Feb 2 – Mar 2 |
| Cabbage | Transplant outdoors (spring) | Mar 2 – Apr 2 |
| Cabbage | Start seeds indoors (fall) | Jun 25 – Jul 25 |
| Cabbage | Transplant outdoors (fall) | Jul 25 – Aug 25 |
| Leaf lettuce | Sow outdoors (spring) | Mar 2 – May 18 |
| Leaf lettuce | Sow outdoors (fall) | Jul 25 – Sep 10 |
| Spinach | Sow outdoors (spring) | Feb 23 – Apr 8 |
| Spinach | Sow outdoors (fall) | Aug 11 – Sep 15 |
| Radishes | Sow outdoors (spring) | Mar 2 – Apr 22 |
| Radishes | Sow outdoors (fall) | Jul 25 – Sep 25 |
| Kale | Sow outdoors (spring) | Mar 19 – Apr 8 |
| Kale | Sow outdoors (fall) | Jul 18 – Aug 25 |
| Carrots | Sow outdoors (spring) | Apr 2 – May 18 |
| Carrots | Sow outdoors (fall) | Jun 25 – Aug 10 |
| Garlic | Plant outdoors (fall) | Oct 25 – Nov 25 |
Where these dates come from
ZIP code 63151 is matched to the NOAA station St Louis Lambert Intl Ap, MO, 13.5 km away, at 531 ft elevation (109 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| St Louis Lambert Intl Ap, MO (used) | 531 ft | Apr 2 | Nov 4 |
| St Charles 7 Ssw, MO | 450 ft | Apr 4 | Oct 29 |
| St Louis Sci Ctr, MO | 515 ft | Apr 1 | Nov 4 |
| St Louis Sprt Of S L Ap, MO | 462 ft | Apr 12 | Oct 23 |
Frost dates near Saint Louis
- Florissant, MO 63032 · last Apr 2, first Nov 4
- Fenton, MO 63099 · last Apr 2, first Nov 4
- Saint Louis, MO 63145 · last Apr 2, first Nov 4
- Chesterfield, MO 63017 · last Apr 4, first Oct 29
- Maryland Heights, MO 63043 · last Apr 2, first Nov 4
- Saint Ann, MO 63074 · last Apr 2, first Nov 4
- Valley Park, MO 63088 · last Apr 4, first Oct 29
- Ballwin, MO 63021 · last Apr 4, first Oct 29
Frequently asked questions
- When is the last frost in Saint Louis, MO?
- For ZIP code 63151, the average last spring frost (32°F) is April 2, based on NOAA 1991-2020 climate normals for the St Louis Lambert Intl Ap, MO weather station. There is a 1-in-10 chance of a frost after April 17.
- When is the first frost in Saint Louis, MO?
- The average first fall frost (32°F) is November 4. There is a 1-in-10 chance of frost by October 23, so tender plants are at risk from that point on.
- How long is the growing season in 63151?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 215 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.