Last spring frost
Mar 30
Frost Dates for Tall Timbers, MD
First fall frost
Nov 14
Growing season
229 days
Hardiness zone
8a
In an average year around Tall Timbers, MD, the last spring frost (32°F) is about Mar 30 and the first fall frost is about Nov 14, giving roughly a 229-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 24 | Apr 10 | Mar 27 |
| Freeze (32°F) | Apr 11 | Mar 30 | Mar 14 |
| Hard (28°F) | Apr 1 | Mar 19 | Feb 28 |
| Severe (24°F) | Mar 22 | Mar 5 | Feb 13 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 24 | Apr 18 | Apr 15 | Apr 12 | Apr 10 | Apr 6 | Apr 3 | Mar 31 | Mar 27 |
| 32°F | Apr 11 | Apr 7 | Apr 3 | Apr 1 | Mar 30 | Mar 27 | Mar 24 | Mar 20 | Mar 14 |
| 28°F | Apr 1 | Mar 29 | Mar 25 | Mar 21 | Mar 19 | Mar 15 | Mar 11 | Mar 6 | Feb 28 |
| 24°F | Mar 22 | Mar 18 | Mar 14 | Mar 10 | Mar 5 | Mar 2 | Feb 27 | Feb 22 | Feb 13 |
| 20°F | Mar 12 | Mar 6 | Mar 1 | Feb 25 | Feb 18 | Feb 13 | Feb 8 | Feb 2 | Jan 25 |
| 16°F | Feb 28 | Feb 19 | Feb 11 | Feb 6 | Feb 2 | Jan 30 | Jan 24 | Jan 17 | Jan 8 |
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 17 | Nov 1 | Nov 15 |
| Freeze (32°F) | Oct 29 | Nov 14 | Dec 1 |
| Hard (28°F) | Nov 11 | Nov 29 | Dec 15 |
| Severe (24°F) | Nov 26 | Dec 11 | Jan 4 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 17 | Oct 22 | Oct 26 | Oct 29 | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 15 |
| 32°F | Oct 29 | Nov 3 | Nov 7 | Nov 10 | Nov 14 | Nov 17 | Nov 20 | Nov 24 | Dec 1 |
| 28°F | Nov 11 | Nov 17 | Nov 20 | Nov 24 | Nov 29 | Dec 1 | Dec 4 | Dec 9 | Dec 15 |
| 24°F | Nov 26 | Dec 1 | Dec 4 | Dec 8 | Dec 11 | Dec 16 | Dec 22 | Dec 28 | Jan 4 |
| 20°F | Dec 6 | Dec 11 | Dec 17 | Dec 23 | Dec 28 | Jan 1 | Jan 6 | Jan 12 | Jan 24 |
| 16°F | Dec 11 | Dec 21 | Dec 29 | Jan 2 | Jan 7 | Jan 12 | Jan 17 | Jan 24 | Feb 2 |
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 Inigoes Webster Nolf, Md, about 5.8 miles away@if(!empty($station['elevation_ft'])), at 21 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 Tall Timbers, MD?
On average, the last spring frost (32°F) around Tall Timbers, MD is about Mar 30. 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 Tall Timbers, MD typically arrives about Nov 14. 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 Mar 30 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 229 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 20674 Planting calendar → Maryland frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026