Frost dates · USDA zone 7b
Frost dates for Rockville, MD
Rockville, MD sees its last 32 °F night of spring around April 1 and its first of fall around November 6 — a 219-day freeze-free season in a typical year.
Pick a sauce; the Plan Builder runs this station's dates and hands back the calendar, plant count and gear list.
Freeze odds, by date
| Odds | Last spring freeze after | First fall freeze before |
|---|---|---|
| 9 years in 10 | Mar 19 | Nov 21 |
| Median — 1 year in 2 | Apr 1 | Nov 6 |
| 1 year in 10 | Apr 15 | Oct 24 |
The top row is the risky edge: in 9 years of 10 a spring freeze still comes after it, so tender transplants set out then need cover. The bottom row is the cautious date — only 1 year in 10 freezes after it — and the one to plan uncovered tender transplants against. Freeze-free season: 219 days median, at least 200 in 9 years of 10, at least 240 days in 1 year of 10. NOAA ranks season length year by year, so it is not the gap between two rows above. A hard freeze (28 °F) has a median last date of Mar 22 and first of Nov 19.
Rockville planting calendar, 2027
Every row runs from the median last frost (Apr 1) and median first frost (Nov 6) above, using each cultivar's days to maturity. Same engine as the Plan Builder.
| Crop | Start indoors | Transplant / plant | First harvest | Days |
|---|---|---|---|---|
| Hardneck GarlicSiberian (porcelain hardneck) | — | Oct 15prior fall | Jun 12 | 240 from sow |
| Spanish OnionYellow Sweet Spanish (long-day) | Jan 7 | Mar 4 | Jun 22 | 110 from transplant |
| Mustard greensGarnet Giant (Brassica juncea) | Direct sow | Apr 1 | May 1 | 30 from sow |
| CilantroSlow Bolt (Coriandrum sativum) | Mar 18 | Mar 18 | May 2 | 45 from sow |
| Genovese BasilGenovese | Mar 4 | Apr 15 | Jun 14 | 60 from transplant |
| CayenneLong Slim Cayenne (Capsicum annuum) | Feb 4 | Apr 8 | Jun 22 | 75 from transplant |
| HabaneroOrange Habanero (Capsicum chinense) | Jan 21 | Apr 15 | Jul 19 | 95 from transplant |
| JalapeñoEarly Jalapeño (Capsicum annuum) | Feb 4 | Apr 8 | Jun 22 | 75 from transplant |
| Marconi Red PepperMarconi Red (Capsicum annuum) | Feb 4 | Apr 8 | Jun 27 | 80 from transplant |
| SerranoSerrano Tampiqueño (Capsicum annuum) | Feb 4 | Apr 8 | Jun 27 | 80 from transplant |
| Nantes CarrotScarlet Nantes | Mar 18 | Mar 18 | May 27 | 70 from sow |
| TomatilloToma Verde | Feb 18 | Apr 8 | Jun 17 | 70 from transplant |
| Roma TomatoRoma VF (determinate paste) | Feb 18 | Apr 8 | Jun 22 | 75 from transplant |
| San Marzano TomatoSan Marzano (indeterminate paste) | Feb 18 | Apr 8 | Jun 27 | 80 from transplant |
Tight means first harvest lands within two weeks of the median first fall frost: start that crop indoors on time or cover it in fall.
What sauce can Rockville grow?
Each sauce, scheduled for a Rockville container garden: when the first seeds go in and when enough fruit has ripened for one batch.
Rockville frost questions
When is the last frost in Rockville, MD?
The median last 32 °F freeze at ROCKVILLE 1 NE, MD is April 1: half of years see a later one. One year in ten, a freeze still comes after April 15; nine years in ten, it comes after March 19. Source: NOAA NCEI 1991–2020 U.S. Climate Normals.
When is the first frost in Rockville, MD?
The median first 32 °F freeze of fall is November 6. One year in ten it arrives before October 24; nine years in ten, before November 21.
How long is the growing season in Rockville, MD?
219 days between the last spring and first fall 32 °F freeze in a median year. Nine years in ten the season runs at least 200 days; one year in ten, at least 240 days.
What growing zone is Rockville, MD?
USDA hardiness zone 7b, per the 2023 USDA Plant Hardiness Zone Map for ZIP 20850. A zone describes the coldest winter night, not when frost ends, so it is the wrong number for a planting calendar — the frost dates on this page are the right one.
When should I plant tomatoes in Rockville, MD?
Start Roma VF (determinate paste) seeds indoors around Feb 18 and transplant around Apr 8, 1 week after the median last frost. To cut the freeze risk to one year in ten, wait for Apr 15. First ripe fruit lands around Jun 22.
When should I plant peppers in Rockville, MD?
Sow jalapeño indoors on a heat mat around Feb 4; transplant no earlier than Apr 8, and wait past it until nights hold above 50 °F — that can run weeks later. First green pods around Jun 22.
Nearby in Maryland
- Gaithersburglast frost Apr 1
- Bowielast frost Apr 22
- Fredericklast frost Apr 2
- Baltimorelast frost Mar 24
- Hagerstownlast frost Apr 7
All Maryland frost dates → · How frost-date math drives a sowing calendar →