Last spring frost
Apr 6
Frost Dates for Marietta, OK
First fall frost
Nov 2
Growing season
211 days
Hardiness zone
8a
In an average year around Marietta, OK, the last spring frost (32°F) is about Apr 6 and the first fall frost is about Nov 2, giving roughly a 211-day growing season. To be safe most years, wait until Mar 16 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 17 | Mar 31 |
| Freeze (32°F) | Apr 24 | Apr 6 | Mar 16 |
| Hard (28°F) | Apr 11 | Mar 23 | Mar 3 |
| Severe (24°F) | Mar 31 | Mar 11 | Feb 21 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 1 | Apr 28 | Apr 24 | Apr 20 | Apr 17 | Apr 13 | Apr 10 | Apr 6 | Mar 31 |
| 32°F | Apr 24 | Apr 18 | Apr 13 | Apr 9 | Apr 6 | Apr 3 | Mar 30 | Mar 24 | Mar 16 |
| 28°F | Apr 11 | Apr 5 | Apr 1 | Mar 28 | Mar 23 | Mar 19 | Mar 15 | Mar 10 | Mar 3 |
| 24°F | Mar 31 | Mar 24 | Mar 19 | Mar 15 | Mar 11 | Mar 8 | Mar 4 | Feb 28 | Feb 21 |
| 20°F | Mar 18 | Mar 11 | Mar 7 | Mar 3 | Feb 27 | Feb 23 | Feb 15 | Feb 6 | Jan 29 |
| 16°F | Mar 6 | Feb 28 | Feb 22 | Feb 12 | Feb 6 | Jan 31 | Jan 27 | Jan 19 | Jan 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 8 | Oct 23 | Nov 5 |
| Freeze (32°F) | Oct 18 | Nov 2 | Nov 16 |
| Hard (28°F) | Oct 24 | Nov 9 | Nov 27 |
| Severe (24°F) | Nov 2 | Nov 21 | Dec 9 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 8 | Oct 14 | Oct 18 | Oct 21 | Oct 23 | Oct 26 | Oct 29 | Nov 1 | Nov 5 |
| 32°F | Oct 18 | Oct 23 | Oct 27 | Oct 30 | Nov 2 | Nov 4 | Nov 7 | Nov 11 | Nov 16 |
| 28°F | Oct 24 | Oct 31 | Nov 3 | Nov 6 | Nov 9 | Nov 13 | Nov 16 | Nov 21 | Nov 27 |
| 24°F | Nov 2 | Nov 7 | Nov 12 | Nov 16 | Nov 21 | Nov 25 | Nov 29 | Dec 3 | Dec 9 |
| 20°F | Nov 12 | Nov 19 | Nov 25 | Nov 28 | Dec 2 | Dec 6 | Dec 12 | Dec 19 | Dec 27 |
| 16°F | Nov 25 | Dec 1 | Dec 6 | Dec 12 | Dec 20 | Dec 25 | Jan 1 | Jan 6 | Jan 16 |
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: Marietta 5Sw, Ok, about 6 miles away@if(!empty($station['elevation_ft'])), at 802 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 Marietta, OK?
On average, the last spring frost (32°F) around Marietta, OK is about Apr 6. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 16.
When is the first frost in the fall?
The first fall frost around Marietta, OK typically arrives about Nov 2. 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 6 on average, or Mar 16 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 211 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 73448 Planting calendar → Oklahoma frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026