Last spring frost
Mar 24
Frost Dates for Baltimore, MD
First fall frost
Nov 21
Growing season
244 days
Hardiness zone
8a
In an average year around Baltimore, MD, the last spring frost (32°F) is about Mar 24 and the first fall frost is about Nov 21, giving roughly a 244-day growing season. To be safe most years, wait until Mar 8 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 15 | Apr 3 | Mar 22 |
| Freeze (32°F) | Apr 4 | Mar 24 | Mar 8 |
| Hard (28°F) | Mar 26 | Mar 11 | Feb 24 |
| Severe (24°F) | Mar 16 | Mar 2 | Feb 9 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 15 | Apr 10 | Apr 8 | Apr 5 | Apr 3 | Apr 1 | Mar 31 | Mar 27 | Mar 22 |
| 32°F | Apr 4 | Apr 1 | Mar 29 | Mar 27 | Mar 24 | Mar 20 | Mar 17 | Mar 13 | Mar 8 |
| 28°F | Mar 26 | Mar 21 | Mar 17 | Mar 15 | Mar 11 | Mar 9 | Mar 6 | Mar 2 | Feb 24 |
| 24°F | Mar 16 | Mar 11 | Mar 8 | Mar 5 | Mar 2 | Feb 28 | Feb 23 | Feb 18 | Feb 9 |
| 20°F | Mar 6 | Mar 1 | Feb 26 | Feb 20 | Feb 15 | Feb 9 | Feb 5 | Jan 31 | Jan 19 |
| 16°F | Feb 25 | Feb 18 | Feb 11 | Feb 6 | Feb 2 | Jan 29 | Jan 22 | Jan 16 | 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 29 | Nov 10 | Nov 24 |
| Freeze (32°F) | Nov 7 | Nov 21 | Dec 8 |
| Hard (28°F) | Nov 18 | Dec 5 | Dec 25 |
| Severe (24°F) | Dec 1 | Dec 23 | Jan 12 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 29 | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 12 | Nov 15 | Nov 18 | Nov 24 |
| 32°F | Nov 7 | Nov 11 | Nov 15 | Nov 18 | Nov 21 | Nov 25 | Nov 29 | Dec 2 | Dec 8 |
| 28°F | Nov 18 | Nov 24 | Nov 28 | Dec 2 | Dec 5 | Dec 9 | Dec 14 | Dec 19 | Dec 25 |
| 24°F | Dec 1 | Dec 8 | Dec 13 | Dec 19 | Dec 23 | Dec 26 | Dec 31 | Jan 5 | Jan 12 |
| 20°F | Dec 11 | Dec 20 | Dec 26 | Dec 31 | Jan 4 | Jan 8 | Jan 12 | Jan 17 | Jan 28 |
| 16°F | Dec 23 | Dec 31 | Jan 5 | Jan 9 | Jan 13 | Jan 17 | Jan 23 | Jan 29 | Feb 7 |
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: Md Sci Ctr Baltimore, Md, about 1.1 miles away@if(!empty($station['elevation_ft'])), at 20 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 Baltimore, MD?
On average, the last spring frost (32°F) around Baltimore, MD is about Mar 24. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 8.
When is the first frost in the fall?
The first fall frost around Baltimore, MD typically arrives about Nov 21. 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 24 on average, or Mar 8 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 244 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 21202 Planting calendar → Maryland frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026