Last spring frost
Apr 5
Frost Dates for Ashton-Sandy Spring, MD
First fall frost
Nov 9
Growing season
218 days
Hardiness zone
7b
In an average year around Ashton-Sandy Spring, MD, the last spring frost (32°F) is about Apr 5 and the first fall frost is about Nov 9, giving roughly a 218-day growing season. To be safe most years, wait until Mar 21 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 2 | Apr 17 | Apr 2 |
| Freeze (32°F) | Apr 19 | Apr 5 | Mar 21 |
| Hard (28°F) | Apr 8 | Mar 25 | Mar 10 |
| Severe (24°F) | Mar 28 | Mar 14 | Feb 25 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 2 | Apr 26 | Apr 23 | Apr 20 | Apr 17 | Apr 14 | Apr 11 | Apr 7 | Apr 2 |
| 32°F | Apr 19 | Apr 14 | Apr 10 | Apr 7 | Apr 5 | Apr 2 | Mar 30 | Mar 26 | Mar 21 |
| 28°F | Apr 8 | Apr 3 | Mar 31 | Mar 28 | Mar 25 | Mar 22 | Mar 19 | Mar 15 | Mar 10 |
| 24°F | Mar 28 | Mar 24 | Mar 20 | Mar 17 | Mar 14 | Mar 11 | Mar 7 | Mar 3 | Feb 25 |
| 20°F | Mar 21 | Mar 16 | Mar 11 | Mar 7 | Mar 3 | Feb 28 | Feb 24 | Feb 18 | Feb 9 |
| 16°F | Mar 12 | Mar 5 | Mar 1 | Feb 25 | Feb 19 | Feb 14 | Feb 7 | Feb 2 | Jan 23 |
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 16 | Oct 29 | Nov 11 |
| Freeze (32°F) | Oct 27 | Nov 9 | Nov 24 |
| Hard (28°F) | Nov 5 | Nov 21 | Dec 8 |
| Severe (24°F) | Nov 15 | Dec 4 | Dec 25 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 16 | Oct 21 | Oct 24 | Oct 26 | Oct 29 | Nov 1 | Nov 3 | Nov 5 | Nov 11 |
| 32°F | Oct 27 | Oct 31 | Nov 3 | Nov 5 | Nov 9 | Nov 11 | Nov 14 | Nov 19 | Nov 24 |
| 28°F | Nov 5 | Nov 10 | Nov 14 | Nov 17 | Nov 21 | Nov 23 | Nov 28 | Dec 2 | Dec 8 |
| 24°F | Nov 15 | Nov 21 | Nov 27 | Dec 1 | Dec 4 | Dec 8 | Dec 14 | Dec 19 | Dec 25 |
| 20°F | Nov 27 | Dec 5 | Dec 10 | Dec 17 | Dec 21 | Dec 26 | Dec 31 | Jan 6 | Jan 13 |
| 16°F | Dec 13 | Dec 21 | Dec 27 | Jan 1 | Jan 5 | Jan 9 | Jan 15 | Jan 21 | Jan 29 |
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: Laurel 3 W, Md, about 6.9 miles away@if(!empty($station['elevation_ft'])), at 400 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 Ashton-Sandy Spring, MD?
On average, the last spring frost (32°F) around Ashton-Sandy Spring, MD is about Apr 5. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 21.
When is the first frost in the fall?
The first fall frost around Ashton-Sandy Spring, MD typically arrives about Nov 9. 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 5 on average, or Mar 21 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 20861 Planting calendar → Maryland frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026