Frost dates for 21402Annapolis, MD
The average last spring frost in Annapolis is March 23 and the average first fall frost is November 20, giving a typical growing season of about 241 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Mar 23
- Average first fall frost
- Nov 20
- Growing season
- 241 days
Safer after Apr 6 (1-in-10 risk)
Possible by Nov 4 (1-in-10 risk)
First frost typically in 17 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 22 · Apr 5 · Apr 20 | Oct 25 · Nov 6 · Nov 21 | 215 days | 100% |
| Frost / freeze (32°F) | Mar 8 · Mar 23 · Apr 6 | Nov 4 · Nov 20 · Dec 5 | 241 days | 100% |
| Hard freeze (28°F) | Feb 24 · Mar 12 · Mar 28 | Nov 16 · Dec 3 · Dec 22 | 266 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 20 – Apr 28 |
| Tomatoes | Transplant outdoors | Apr 8 – Jul 31 |
| Peppers | Start seeds indoors | Feb 20 – Mar 23 |
| Peppers | Transplant outdoors | Apr 22 – May 23 |
| Eggplant | Start seeds indoors | Mar 9 – Apr 7 |
| Eggplant | Transplant outdoors | Apr 22 – May 23 |
| Cucumbers | Sow outdoors | Apr 22 – Aug 10 |
| Summer squash | Sow outdoors | Apr 8 – May 23 |
| Winter squash & pumpkins | Sow outdoors | Apr 22 – May 23 |
| Snap beans | Sow outdoors | Apr 8 – Sep 2 |
| Sweet corn | Sow outdoors | Apr 8 – Jul 31 |
| Watermelon & cantaloupe | Sow outdoors | Apr 22 – May 23 |
| Okra | Sow outdoors | Apr 15 – May 8 |
| Peas | Sow outdoors (spring) | Feb 20 – Apr 7 |
| Potatoes | Plant outdoors (spring) | Feb 20 – Apr 22 |
| Onions | Start seeds indoors (spring) | Jan 9 – Feb 5 |
| Onions | Transplant outdoors (spring) | Mar 9 – Apr 7 |
| Broccoli | Start seeds indoors (spring) | Feb 2 – Mar 8 |
| Broccoli | Transplant outdoors (spring) | Mar 9 – Apr 7 |
| Broccoli | Start seeds indoors (fall) | Jul 21 – Jul 31 |
| Broccoli | Transplant outdoors (fall) | Aug 20 – Aug 31 |
| Cabbage | Start seeds indoors (spring) | Jan 23 – Feb 20 |
| Cabbage | Transplant outdoors (spring) | Feb 20 – Mar 23 |
| Cabbage | Start seeds indoors (fall) | Jul 11 – Aug 10 |
| Cabbage | Transplant outdoors (fall) | Aug 10 – Sep 10 |
| Leaf lettuce | Sow outdoors (spring) | Feb 20 – May 8 |
| Leaf lettuce | Sow outdoors (fall) | Aug 10 – Sep 26 |
| Spinach | Sow outdoors (spring) | Feb 13 – Mar 29 |
| Spinach | Sow outdoors (fall) | Aug 27 – Oct 1 |
| Radishes | Sow outdoors (spring) | Feb 20 – Apr 12 |
| Radishes | Sow outdoors (fall) | Aug 10 – Oct 11 |
| Kale | Sow outdoors (spring) | Mar 9 – Mar 29 |
| Kale | Sow outdoors (fall) | Aug 3 – Sep 10 |
| Carrots | Sow outdoors (spring) | Mar 23 – May 8 |
| Carrots | Sow outdoors (fall) | Jul 11 – Aug 26 |
| Garlic | Plant outdoors (fall) | Nov 10 – Dec 11 |
Where these dates come from
ZIP code 21402 is matched to the NOAA station Annapolis Naf, MD, 0.6 km away, at 8 ft elevation (38 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Annapolis Naf, MD (used) | 8 ft | Mar 23 | Nov 20 |
| Annapolis Police Brks, MD | 25 ft | Mar 27 | Nov 13 |
| Stevensville 2Sw, MD | 10 ft | Mar 29 | Nov 12 |
| Baltimore Wash Intl Ap, MD | 156 ft | Apr 10 | Oct 31 |
Frost dates near Annapolis
- Annapolis, MD 21404 · last Mar 27, first Nov 13
- Arnold, MD 21012 · last Mar 27, first Nov 13
- Edgewater, MD 21037 · last Apr 9, first Oct 29
- Gibson Island, MD 21056 · 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
- Mayo, MD 21106 · last Mar 23, first Nov 20
Frequently asked questions
- When is the last frost in Annapolis, MD?
- For ZIP code 21402, the average last spring frost (32°F) is March 23, based on NOAA 1991-2020 climate normals for the Annapolis Naf, MD weather station. There is a 1-in-10 chance of a frost after April 6.
- When is the first frost in Annapolis, MD?
- The average first fall frost (32°F) is November 20. There is a 1-in-10 chance of frost by November 4, so tender plants are at risk from that point on.
- How long is the growing season in 21402?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 241 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.