When to plant in Grand Forks, ND
USDA Zone 4aHere are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Grand Forks, North Dakota — all computed from Grand Forks's nearest NOAA weather station.
In zone 4a, Grand Forks winters are severe; choose cold-hardy perennials and time annuals carefully around the frost dates above.
Frost probability
GRAND FORKS UNIV (NWS) · 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 Grand Forks’s own odds, recorded at GRAND FORKS UNIV (NWS).
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | Jun 1 | May 19 | May 7 | Sep 10 | Sep 23 | Oct 3 |
| 32°F | May 24 | May 10 | Apr 28 | Sep 20 | Oct 1 | Oct 15 |
| 28°F | May 14 | Apr 30 | Apr 16 | Sep 29 | Oct 12 | Oct 25 |
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 Grand Forks, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 37 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.
Grand Forks planting FAQ
When is the last spring frost in Grand Forks, ND?
Grand Forks's average last spring frost falls near May 10 — 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 Grand Forks, ND?
Expect Grand Forks's first fall frost near October 1 — a 50% chance of 32°F by that date. Bring in or cover tender crops ahead of it.
What hardiness zone is Grand Forks in?
Grand Forks is in USDA hardiness zone 4a. In zone 4a, winters are cold — pick cold-hardy varieties and protect tender crops.
How long is the growing season in Grand Forks?
Grand Forks has about 144 frost-free days — a short growing season — between the average last spring frost (May 10) and first fall frost (October 1).
When should I plant tomatoes in Grand Forks?
For Grand Forks, sow tomatoes indoors about March 15–March 29 and move the seedlings out around May 17, after the last spring frost.
Never miss a window in Grand Forks
An email when it’s time to start seeds, transplant, and sow — timed to Grand Forks’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Fargo · 119 km
- West Fargo · 119 km
- Moorhead · 120 km
- Detroit Lakes · 155 km
- Jamestown · 165 km
- Bemidji · 172 km
- Fergus Falls · 197 km
- Alexandria · 262 km
Frost dates recorded at GRAND FORKS UNIV (NWS), 1 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 Grand Forks, ND — Frost Dates & Zone 4a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00323621. Retrieved from https://blissgarden.com/north-dakota/grand-forks.