Last spring frost
Apr 4
Frost Dates for Ashburn, MO
First fall frost
Nov 4
Growing season
212 days
Hardiness zone
6b
In an average year around Ashburn, MO, the last spring frost (32°F) is about Apr 4 and the first fall frost is about Nov 4, giving roughly a 212-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) | Apr 30 | Apr 14 | Apr 2 |
| Freeze (32°F) | Apr 19 | Apr 4 | Mar 20 |
| Hard (28°F) | Apr 8 | Mar 26 | Mar 8 |
| Severe (24°F) | Apr 2 | Mar 15 | Feb 28 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 30 | Apr 25 | Apr 21 | Apr 18 | Apr 14 | Apr 11 | Apr 8 | Apr 5 | Apr 2 |
| 32°F | Apr 19 | Apr 13 | Apr 9 | Apr 7 | Apr 4 | Apr 2 | Mar 31 | Mar 25 | Mar 20 |
| 28°F | Apr 8 | Apr 4 | Apr 1 | Mar 30 | Mar 26 | Mar 22 | Mar 18 | Mar 14 | Mar 8 |
| 24°F | Apr 2 | Mar 28 | Mar 23 | Mar 19 | Mar 15 | Mar 12 | Mar 8 | Mar 4 | Feb 28 |
| 20°F | Mar 24 | Mar 17 | Mar 13 | Mar 10 | Mar 6 | Mar 3 | Mar 1 | Feb 26 | Feb 19 |
| 16°F | Mar 16 | Mar 10 | Mar 7 | Mar 4 | Mar 1 | Feb 27 | Feb 21 | Feb 16 | Feb 6 |
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 12 | Oct 24 | Nov 5 |
| Freeze (32°F) | Oct 23 | Nov 4 | Nov 18 |
| Hard (28°F) | Nov 1 | Nov 14 | Nov 30 |
| Severe (24°F) | Nov 7 | Nov 22 | Dec 9 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 12 | Oct 17 | Oct 20 | Oct 22 | Oct 24 | Oct 26 | Oct 29 | Nov 1 | Nov 5 |
| 32°F | Oct 23 | Oct 28 | Oct 31 | Nov 1 | Nov 4 | Nov 6 | Nov 9 | Nov 13 | Nov 18 |
| 28°F | Nov 1 | Nov 4 | Nov 8 | Nov 10 | Nov 14 | Nov 16 | Nov 20 | Nov 24 | Nov 30 |
| 24°F | Nov 7 | Nov 11 | Nov 15 | Nov 19 | Nov 22 | Nov 26 | Nov 30 | Dec 3 | Dec 9 |
| 20°F | Nov 14 | Nov 20 | Nov 25 | Nov 29 | Dec 1 | Dec 5 | Dec 9 | Dec 13 | Dec 19 |
| 16°F | Nov 23 | Nov 30 | Dec 3 | Dec 6 | Dec 11 | Dec 16 | Dec 20 | Dec 24 | Dec 30 |
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: Saverton L&D 22, Mo, about 11.2 miles away@if(!empty($station['elevation_ft'])), at 472 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 Ashburn, MO?
On average, the last spring frost (32°F) around Ashburn, 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 Ashburn, 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 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 212 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 63433 Planting calendar → Missouri frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026