When to plant in Gaithersburg, MD
USDA Zone 7bEverything below — frost dates, hardiness zone, and what to plant when in Gaithersburg, Maryland — is derived from the closest NOAA station with complete climate normals.
Zone 7b means many perennials and even some tender shrubs overwinter in Gaithersburg, while your frost dates still decide when annuals go out.
Frost probability
ROCKVILLE 1 NE · 1991–2020The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Gaithersburg’s own odds, recorded at ROCKVILLE 1 NE.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 5 | Apr 16 | Mar 31 | Oct 12 | Oct 25 | Nov 7 |
| 32°F | Apr 15 | Apr 1 | Mar 19 | Oct 24 | Nov 6 | Nov 21 |
| 28°F | Apr 4 | Mar 22 | Mar 5 | Nov 5 | Nov 19 | Dec 6 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Full-year planting calendar
Each bar is the exact window to take a planting action in Gaithersburg, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 24 km · complete 32°F normalsWhen stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.
Gaithersburg planting FAQ
When is the last spring frost in Gaithersburg, MD?
Gaithersburg's average last spring frost falls near April 1 — the 50% mark at 32°F in the 1991–2020 normals. Hold tender transplants until the risk has passed, then plant out.
When is the first fall frost in Gaithersburg, MD?
In Gaithersburg, the first 32°F freeze of fall lands around November 6 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is Gaithersburg in?
Gaithersburg is in USDA hardiness zone 7b. In zone 7b, winters are moderate — most common vegetables grow well in season.
How long is the growing season in Gaithersburg?
There are roughly 219 frost-free days in Gaithersburg (a long growing season), running from the average last frost around April 1 to the first fall frost near November 6.
When should I plant tomatoes in Gaithersburg?
In Gaithersburg, start tomato seeds indoors around February 4–February 18, then transplant seedlings outdoors around April 8 once the danger of frost has passed.
Never miss a window in Gaithersburg
An email when it’s time to start seeds, transplant, and sow — timed to Gaithersburg’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Flower Hill · 2 km
- Montgomery Village · 5 km
- Redland · 5 km
- Germantown · 7 km
- North Potomac · 7 km
- Rockville · 8 km
- Clarksburg · 10 km
- Olney · 11 km
Frost dates recorded at ROCKVILLE 1 NE, 7 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.
BlissGarden. "When to Plant in Gaithersburg, MD — Frost Dates & Zone 7b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00187705. Retrieved from https://blissgarden.com/maryland/gaithersburg.