In North Dakota, the last spring frost usually comes between May 10 and May 25, and the first fall frost between September 16 and September 28, depending on where you live. Most of North Dakota is in USDA hardiness zones 3b to 4b.
Find the frost dates for your ZIP code
Frost dates from NOAA 1991–2020 U.S. Climate Normals, nearest weather station. Zones derived from the 2023 USDA Plant Hardiness Zone Map data (PRISM Climate Group, Oregon State University). This is not the official USDA Plant Hardiness Zone Map.
Frost dates for North Dakota cities
Dates come from the NOAA weather station closest to each city. The last spring frost and first fall frost are the typical dates, with a 30% chance of frost after (or before) them. The safer planting date has only a 10% chance of a later spring frost: use it for tender plants like tomatoes, peppers and basil.
| City | Zone | Last frost | Safer date | First frost |
|---|---|---|---|---|
| Fargo | 4a | May 15 | May 23 | Sep. 25 |
| Bismarck | 4a | May 14 | May 23 | Sep. 25 |
| Grand Forks | 4a | May 16 | May 24 | Sep. 26 |
| Minot | 4a | May 15 | May 22 | Sep. 27 |
| Williston | 4a | May 18 | May 25 | Sep. 22 |
| Dickinson | 4b | May 25 | June 1 | Sep. 16 |
| Jamestown | 4b | May 16 | May 24 | Sep. 23 |
| Wahpeton | 4a | May 10 | May 17 | Sep. 28 |
| Devils Lake | 4a | May 17 | May 24 | Sep. 26 |
| Watford City | 4a | May 14 | May 22 | Sep. 22 |
Frost dates vary a lot across North Dakota. Among the cities above, Wahpeton has the earliest last frost (around May 10) and Dickinson the latest (around May 25), about 2 weeks apart. Elevation, nearby water and local terrain all make a difference, so use the dates for the place closest to you, or look up your ZIP code.
Growing zones in North Dakota
Most of North Dakota is in USDA hardiness zones 3b to 4b. A typical frost-free growing season lasts about 145 days, longer in the warmest areas and shorter in the coldest.
Find planting dates for the main zones in North Dakota:
- Zone 3 (about 13% of ZIP codes): Tomatoes, Peppers, Potatoes, Lettuce, Green beans, Cucumbers, Garlic, Tulips
- Zone 4 (about 87% of ZIP codes): Tomatoes, Peppers, Potatoes, Lettuce, Green beans, Cucumbers, Garlic, Tulips
See all crops in our planting guides, or build a planting calendar for your ZIP code.
How to use frost dates
- Cool-season crops such as peas, lettuce, spinach and onions can go in several weeks before your last spring frost.
- Warm-season crops such as tomatoes, peppers, squash and beans wait until after it, when the soil has warmed.
- Fall crops are timed back from your first fall frost, and garlic and tulips are planted around it.
- Frost dates are averages. Check the forecast before setting out tender plants.
Frequently asked questions
When is the last frost in North Dakota?
It depends on where you live. Across most of North Dakota, the last spring frost comes between May 10 and May 25. In Fargo, it is around May 15.
When is the first frost in North Dakota?
Across most of North Dakota, the first fall frost comes between September 16 and September 28. In Fargo, it is around September 25.
What planting zone is North Dakota?
Most of North Dakota is in USDA hardiness zones 3b to 4b. Enter your ZIP code above to find your exact zone.
When can I plant tomatoes in North Dakota?
Plant tomatoes outside after your last frost, once nights stay above 50 °F. In Fargo, the safer date, with only a 10% chance of a later frost, is around May 23. See when to plant tomatoes in zone 4.
Sources. Frost dates come from the nearest NOAA weather station to each city or ZIP code. Zones come from the 2023 USDA Plant Hardiness Zone Map ZIP code data. Our zone lookup is not the official USDA map.