Frost dates for Watford City, ND
At Watford City, the median last spring frost (32°F) is May 9 and the median first fall frost is Sep 27, for a typical growing season of 139 days. For a 90% chance that the last frost has passed, wait until May 22. Nearby ZIP codes are in USDA hardiness zone 4a.
- May 9Last spring frost (median)50% chance of 32°F after this date
- May 22Safer planting date10% chance of 32°F after this date
- Sep 27First fall frost (median)50% chance of 32°F by this date
- 139 daysGrowing season (median)between 32°F freezes
Last spring frost dates
The chance that the temperature drops to the threshold after each date.
| Temperature | 90% chance later | 50% chance later | 10% chance later |
|---|---|---|---|
| 36°F | May 8 | May 19 | Jun 1 |
| 32°F | Apr 28 | May 9 | May 22 |
| 28°F | Apr 16 | Apr 30 | May 13 |
| 24°F | Apr 6 | Apr 18 | May 2 |
First fall frost dates
The chance that the temperature has dropped to the threshold by each date.
| Temperature | 10% chance by | 50% chance by | 90% chance by |
|---|---|---|---|
| 36°F | Sep 8 | Sep 20 | Oct 1 |
| 32°F | Sep 15 | Sep 27 | Oct 11 |
| 28°F | Sep 23 | Oct 7 | Oct 22 |
| 24°F | Oct 1 | Oct 17 | Nov 1 |
Growing season length
Days between the last spring and first fall freeze, as the length reached in 9, 5 and 1 out of 10 years.
| Temperature | 9 in 10 years at least | 5 in 10 years at least | 1 in 10 years at least |
|---|---|---|---|
| 36°F | 103 days | 122 days | 140 days |
| 32°F | 122 days | 139 days | 159 days |
| 28°F | 139 days | 160 days | 180 days |
| 24°F | 159 days | 180 days | 200 days |
Chance of a freeze in any year
| Temperature | Chance per year |
|---|---|
| 36°F | 100% |
| 32°F | 100% |
| 28°F | 100% |
| 24°F | 100% |
ZIP codes whose closest station is this one
| ZIP | Hardiness zone | Avg. extreme low | Distance |
|---|---|---|---|
| 58854 | 4a | -30 to -25°F | 11 km |
| 58835 | 4a | -30 to -25°F | 14 km |
| 58831 | 4a | -30 to -25°F | 28 km |
Not the official USDA Plant Hardiness Zone Map. Zones shown here are the values published in the USDA-ARS / Oregon State University PRISM Group 2023 ZIP code tables, shown unaltered. For the official interactive map, visit planthardiness.ars.usda.gov.
About this station
- NOAA station ID USC00329233, at 47.8039, -103.2892, elevation 661 m (2,170 ft).
- Data quality: Representative (10+ years), 24 years of freeze data.
- Average days per year at or below 32°F: 194.
- Frost risk changes over short distances. Valleys and low spots freeze earlier than hillsides and city centers.
Nearby weather stations
- Watford City 14s (23 km)
- Keene 3s (29 km)
- Grassy Butte 2ene (45 km)
- Williston Sloulin Intl Airport (49 km)
- Williston Exp. Farm (50 km)
- Killdeer (62 km)
- Fairfield (68 km)
- Tioga 1e (72 km)
Sources
- NOAA National Centers for Environmental Information, U.S. Climate Normals 1991–2020, annual/seasonal normals by station (version 1.0.1), file dated June 27, 2023; documentation.
- USDA Agricultural Research Service and PRISM Group, Oregon State University, 2023 Plant Hardiness Zone Map ZIP code tables (CONUS, Alaska, Hawaii, Puerto Rico), files dated November 17, 2023. Data © PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed November 1, 2026. Official map: planthardiness.ars.usda.gov.
- U.S. Census Bureau, 2024 Gazetteer ZIP Code Tabulation Areas file, dated August 30, 2024 (ZIP centroids used to find the nearest station).
Freeze dates are 30-year probabilities, not forecasts. Check your local forecast before planting tender plants.