Last spring frost
Apr 1
Frost Dates for St. Louis, MO
First fall frost
Nov 4
Growing season
218 days
Hardiness zone
7a
In an average year around St. Louis, MO, the last spring frost (32°F) is about Apr 1 and the first fall frost is about Nov 4, giving roughly a 218-day growing season. To be safe most years, wait until Mar 14 before setting out tender plants.
Last spring frost
Dates the last frost of spring typically ends. Plant tender crops after the risk has passed for your comfort level.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Apr 27 | Apr 12 | Mar 27 |
| Freeze (32°F) | Apr 18 | Apr 1 | Mar 14 |
| Hard (28°F) | Apr 7 | Mar 22 | Mar 5 |
| Severe (24°F) | Mar 29 | Mar 11 | Feb 22 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 27 | Apr 22 | Apr 19 | Apr 16 | Apr 12 | Apr 9 | Apr 5 | Apr 2 | Mar 27 |
| 32°F | Apr 18 | Apr 11 | Apr 7 | Apr 4 | Apr 1 | Mar 29 | Mar 26 | Mar 21 | Mar 14 |
| 28°F | Apr 7 | Apr 3 | Mar 30 | Mar 26 | Mar 22 | Mar 18 | Mar 15 | Mar 10 | Mar 5 |
| 24°F | Mar 29 | Mar 22 | Mar 17 | Mar 14 | Mar 11 | Mar 7 | Mar 4 | Feb 28 | Feb 22 |
| 20°F | Mar 18 | Mar 13 | Mar 8 | Mar 5 | Mar 2 | Feb 28 | Feb 24 | Feb 18 | Feb 11 |
| 16°F | Mar 11 | Mar 5 | Mar 2 | Feb 28 | Feb 23 | Feb 18 | Feb 13 | Feb 6 | Jan 31 |
First fall frost
Dates the first frost of fall typically arrives. Count back by a crop's days-to-maturity to know your planting cutoff.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Oct 15 | Oct 26 | Nov 7 |
| Freeze (32°F) | Oct 24 | Nov 4 | Nov 21 |
| Hard (28°F) | Nov 2 | Nov 15 | Dec 4 |
| Severe (24°F) | Nov 9 | Nov 26 | Dec 15 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 15 | Oct 18 | Oct 21 | Oct 24 | Oct 26 | Oct 29 | Oct 31 | Nov 2 | Nov 7 |
| 32°F | Oct 24 | Oct 28 | Oct 31 | Nov 2 | Nov 4 | Nov 7 | Nov 10 | Nov 14 | Nov 21 |
| 28°F | Nov 2 | Nov 5 | Nov 8 | Nov 12 | Nov 15 | Nov 19 | Nov 23 | Nov 28 | Dec 4 |
| 24°F | Nov 9 | Nov 14 | Nov 18 | Nov 22 | Nov 26 | Dec 1 | Dec 4 | Dec 8 | Dec 15 |
| 20°F | Nov 19 | Nov 25 | Nov 30 | Dec 3 | Dec 6 | Dec 12 | Dec 16 | Dec 21 | Dec 28 |
| 16°F | Nov 28 | Dec 3 | Dec 8 | Dec 14 | Dec 19 | Dec 23 | Dec 28 | Jan 1 | Jan 11 |
Growing season is measured at 32°F with about 50% probability. Hardiness zone from the 2023 USDA map; frost normals from NOAA 1991-2020.
Where this data comes from
@endif These dates are computed from the nearest official weather station with long-term records: St Louis Sci Ctr, Mo, about 0.4 miles away@if(!empty($station['elevation_ft'])), at 515 ft elevation. The further the station and the greater the elevation difference from your yard, the more your local frost timing can vary.
How we calculate these dates
Frost and freeze dates come from the NOAA 1991–2020 U.S. Climate Normals, the National Oceanic and Atmospheric Administration's 30-year averages for each weather station. A date shown at the 50% level is the median: in half of years the frost falls on or before it. The 10% and 90% columns show the early and late ends of the range, so you can plant on the odds you're comfortable with. These are long-term averages, not a forecast for this year - always check your local outlook before planting.
Source: NOAA National Centers for Environmental Information, 1991–2020 Climate Normals (public domain). Harman is not affiliated with or endorsed by NOAA.
Frequently asked questions
When is the last frost in St. Louis, MO?
On average, the last spring frost (32°F) around St. Louis, MO is about Apr 1. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 14.
When is the first frost in the fall?
The first fall frost around St. Louis, MO typically arrives about Nov 4. Count back by a crop's days to maturity to find the latest date you can plant it.
When can I plant tomatoes and other tender crops?
Tender crops like tomatoes, peppers and basil are damaged by frost, so wait until the last spring frost has passed - around Apr 1 on average, or Mar 14 to be safe most years.
How long is the growing season here?
The frost-free growing season (between the last spring and first fall 32°F frost) is about 218 days in a typical year.
Are these dates a forecast for this year?
No. They are 30-year averages from the NOAA 1991–2020 Climate Normals, not a prediction for the current year. Use them for planning and always check your local weather forecast before planting or protecting crops.
Local weather for 63110 Planting calendar → Missouri frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026