Last spring frost
Apr 4
Frost Dates for Maryland Heights, MO
First fall frost
Oct 29
Growing season
206 days
Hardiness zone
7a
In an average year around Maryland Heights, MO, the last spring frost (32°F) is about Apr 4 and the first fall frost is about Oct 29, giving roughly a 206-day growing season. To be safe most years, wait until Mar 20 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) | May 1 | Apr 16 | Apr 3 |
| Freeze (32°F) | Apr 21 | Apr 4 | Mar 20 |
| Hard (28°F) | Apr 8 | Mar 25 | Mar 8 |
| Severe (24°F) | Mar 30 | Mar 14 | Feb 27 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 1 | Apr 26 | Apr 22 | Apr 19 | Apr 16 | Apr 13 | Apr 10 | Apr 7 | Apr 3 |
| 32°F | Apr 21 | Apr 14 | Apr 10 | Apr 7 | Apr 4 | Apr 2 | Mar 31 | Mar 27 | Mar 20 |
| 28°F | Apr 8 | Apr 3 | Mar 31 | Mar 29 | Mar 25 | Mar 22 | Mar 18 | Mar 13 | Mar 8 |
| 24°F | Mar 30 | Mar 26 | Mar 21 | Mar 17 | Mar 14 | Mar 11 | Mar 7 | Mar 4 | Feb 27 |
| 20°F | Mar 20 | Mar 15 | Mar 12 | Mar 8 | Mar 5 | Mar 2 | Feb 28 | Feb 24 | Feb 16 |
| 16°F | Mar 13 | Mar 8 | Mar 5 | Mar 1 | Feb 26 | Feb 23 | Feb 18 | Feb 12 | Feb 4 |
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 5 | Oct 19 | Oct 31 |
| Freeze (32°F) | Oct 15 | Oct 29 | Nov 11 |
| Hard (28°F) | Oct 27 | Nov 8 | Nov 27 |
| Severe (24°F) | Nov 4 | Nov 20 | Dec 7 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 5 | Oct 11 | Oct 14 | Oct 16 | Oct 19 | Oct 21 | Oct 24 | Oct 27 | Oct 31 |
| 32°F | Oct 15 | Oct 20 | Oct 24 | Oct 27 | Oct 29 | Oct 31 | Nov 2 | Nov 6 | Nov 11 |
| 28°F | Oct 27 | Nov 1 | Nov 2 | Nov 5 | Nov 8 | Nov 11 | Nov 16 | Nov 21 | Nov 27 |
| 24°F | Nov 4 | Nov 8 | Nov 12 | Nov 16 | Nov 20 | Nov 24 | Nov 27 | Dec 1 | Dec 7 |
| 20°F | Nov 10 | Nov 18 | Nov 23 | Nov 27 | Dec 1 | Dec 4 | Dec 8 | Dec 12 | Dec 20 |
| 16°F | Nov 23 | Nov 28 | Dec 2 | Dec 7 | Dec 11 | Dec 16 | Dec 21 | Dec 25 | Jan 1 |
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 Charles 7 Ssw, Mo, about 2.6 miles away@if(!empty($station['elevation_ft'])), at 450 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 Maryland Heights, MO?
On average, the last spring frost (32°F) around Maryland Heights, MO is about Apr 4. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 20.
When is the first frost in the fall?
The first fall frost around Maryland Heights, MO typically arrives about Oct 29. 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 4 on average, or Mar 20 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 206 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 63146 Planting calendar → Missouri frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026