When to plant in St. Marys, GA
USDA Zone 9aSt. Marys, Georgia frost dates, USDA zone, and a full-year planting calendar, drawn from the nearest NOAA station and tuned to the local season.
St. Marys enjoys a long ~298-day frost-free season — you can succession-sow, fit in a second crop, and grow long-season heat-lovers with room to spare. In zone 9a, frost is a minor factor for St. Marys — most perennials thrive, and annual vegetables can go out early and stay late.
Frost probability
BRUNSWICK 23 S · 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 St. Marys’s own odds, recorded at BRUNSWICK 23 S.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Mar 31 | Mar 5 | Feb 12 | Nov 11 | Nov 29 | Dec 22 |
| 32°F | Mar 14 | Feb 19 | Jan 19 | Nov 21 | Dec 14 | Jan 15 |
| 28°F | Feb 28 | Feb 3 | Dec 31 | Dec 2 | Jan 3 | Feb 7 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Nothing new to sow or transplant outdoors in the next few weeks — a seasonal lull. Check the full-year calendar below for the next window.
Full-year planting calendar
Each bar is the exact window to take a planting action in St. Marys, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 26 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.
St. Marys planting FAQ
When is the last spring frost in St. Marys, GA?
St. Marys's average last spring frost falls near February 19 — 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 St. Marys, GA?
The first fall frost in St. Marys typically arrives around December 14 (50% probability at 32°F). Harvest or protect frost-sensitive crops before then.
What hardiness zone is St. Marys in?
St. Marys is in USDA hardiness zone 9a. In zone 9a, winters are mild — many tender perennials overwinter here.
How long is the growing season in St. Marys?
St. Marys has about 298 frost-free days — a long growing season — between the average last spring frost (February 19) and first fall frost (December 14).
When should I plant tomatoes in St. Marys?
For St. Marys, sow tomatoes indoors about December 25–January 8 and move the seedlings out around February 26, after the last spring frost.
Never miss a window in St. Marys
An email when it’s time to start seeds, transplant, and sow — timed to St. Marys’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Yulee · 14 km
- Fernandina Beach · 16 km
- Kingsland · 23 km
- Brunswick · 44 km
- Jacksonville · 47 km
- Atlantic Beach · 50 km
- St. Simons · 51 km
- Jacksonville Beach · 57 km
Frost dates recorded at BRUNSWICK 23 S, 13 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 St. Marys, GA — Frost Dates & Zone 9a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USW00063856. Retrieved from https://blissgarden.com/georgia/st-marys.