Frost dates for 21403Annapolis, MD
The average last spring frost in Annapolis is March 27 and the average first fall frost is November 13, giving a typical growing season of about 234 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Mar 27
- Average first fall frost
- Nov 13
- Growing season
- 234 days
Safer after Apr 9 (1-in-10 risk)
Possible by Nov 1 (1-in-10 risk)
First frost typically in 10 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | Mar 24 · Apr 7 · Apr 24 | Oct 21 · Nov 2 · Nov 15 | 210 days | 100% |
| Frost / freeze (32°F) | Mar 9 · Mar 27 · Apr 9 | Nov 1 · Nov 13 · Dec 1 | 234 days | 100% |
| Hard freeze (28°F) | Feb 26 · Mar 14 · Mar 29 | Nov 9 · Nov 28 · Dec 19 | 259 days | 100% |
Planting calendar for Annapolis
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Feb 24 – May 2 |
| Tomatoes | Transplant outdoors | Apr 12 – Jul 24 |
| Peppers | Start seeds indoors | Feb 24 – Mar 27 |
| Peppers | Transplant outdoors | Apr 26 – May 27 |
| Eggplant | Start seeds indoors | Mar 13 – Apr 11 |
| Eggplant | Transplant outdoors | Apr 26 – May 27 |
| Cucumbers | Sow outdoors | Apr 26 – Aug 3 |
| Summer squash | Sow outdoors | Apr 12 – May 27 |
| Winter squash & pumpkins | Sow outdoors | Apr 26 – May 27 |
| Snap beans | Sow outdoors | Apr 12 – Aug 26 |
| Sweet corn | Sow outdoors | Apr 12 – Jul 24 |
| Watermelon & cantaloupe | Sow outdoors | Apr 26 – May 27 |
| Okra | Sow outdoors | Apr 19 – May 12 |
| Peas | Sow outdoors (spring) | Feb 24 – Apr 11 |
| Potatoes | Plant outdoors (spring) | Feb 24 – Apr 26 |
| Onions | Start seeds indoors (spring) | Jan 13 – Feb 9 |
| Onions | Transplant outdoors (spring) | Mar 13 – Apr 11 |
| Broccoli | Start seeds indoors (spring) | Feb 6 – Mar 12 |
| Broccoli | Transplant outdoors (spring) | Mar 13 – Apr 11 |
| Broccoli | Start seeds indoors (fall) | Jul 14 – Jul 24 |
| Broccoli | Transplant outdoors (fall) | Aug 13 – Aug 24 |
| Cabbage | Start seeds indoors (spring) | Jan 27 – Feb 24 |
| Cabbage | Transplant outdoors (spring) | Feb 24 – Mar 27 |
| Cabbage | Start seeds indoors (fall) | Jul 4 – Aug 3 |
| Cabbage | Transplant outdoors (fall) | Aug 3 – Sep 3 |
| Leaf lettuce | Sow outdoors (spring) | Feb 24 – May 12 |
| Leaf lettuce | Sow outdoors (fall) | Aug 3 – Sep 19 |
| Spinach | Sow outdoors (spring) | Feb 17 – Apr 2 |
| Spinach | Sow outdoors (fall) | Aug 20 – Sep 24 |
| Radishes | Sow outdoors (spring) | Feb 24 – Apr 16 |
| Radishes | Sow outdoors (fall) | Aug 3 – Oct 4 |
| Kale | Sow outdoors (spring) | Mar 13 – Apr 2 |
| Kale | Sow outdoors (fall) | Jul 27 – Sep 3 |
| Carrots | Sow outdoors (spring) | Mar 27 – May 12 |
| Carrots | Sow outdoors (fall) | Jul 4 – Aug 19 |
| Garlic | Plant outdoors (fall) | Nov 3 – Dec 4 |
Where these dates come from
ZIP code 21403 is matched to the NOAA station Annapolis Police Brks, MD, 4.8 km away, at 25 ft elevation (1 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Annapolis Police Brks, MD (used) | 25 ft | Mar 27 | Nov 13 |
| Annapolis Naf, MD | 8 ft | Mar 23 | Nov 20 |
| Stevensville 2Sw, MD | 10 ft | Mar 29 | Nov 12 |
| Upper Marlboro 3 Nnw, MD | 130 ft | Apr 9 | Oct 29 |
Frost dates near Annapolis
- Annapolis, MD 21404 · last Mar 27, first Nov 13
- Edgewater, MD 21037 · last Apr 9, first Oct 29
- Mayo, MD 21106 · last Mar 23, first Nov 20
- Riva, MD 21140 · last Apr 9, first Oct 29
- Glen Burnie, MD 21062 · last Apr 9, first Oct 29
- Pasadena, MD 21123 · last Apr 9, first Oct 29
- Arnold, MD 21012 · last Mar 27, first Nov 13
- Davidsonville, MD 21035 · last Apr 9, first Oct 29
Frequently asked questions
- When is the last frost in Annapolis, MD?
- For ZIP code 21403, the average last spring frost (32°F) is March 27, based on NOAA 1991-2020 climate normals for the Annapolis Police Brks, MD weather station. There is a 1-in-10 chance of a frost after April 9.
- When is the first frost in Annapolis, MD?
- The average first fall frost (32°F) is November 13. There is a 1-in-10 chance of frost by November 1, so tender plants are at risk from that point on.
- How long is the growing season in 21403?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 234 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.