USDA Hardiness Zone 3b
Frost Dates for 58316 — Belcourt, North Dakota
NOAA 1991–2020 normals from Belcourt Keya Radio, ND (1,960 ft), under a mile northeast.
Updated
In Belcourt, the last spring frost (32°F) is around May 19 in half of years and has passed by June 1 in nine years out of ten. The first fall frost comes around September 24, as early as September 10 one year in ten, leaving a typical freeze-free season of 126 days (NOAA, Belcourt Keya Radio, ND).
- Last spring frost
- May 19
- First fall frost
- September 24
- Growing season
- 126 days
- Hardiness zone
- 3b
50% probability
50% probability
freeze-free, 50%
-35 to -30°F (-37.2 to -34.4°C) coldest night
- First snow
- November 7
- Last snow
- March 31
- Winters with snow
- 100%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
25 of 25 observed
NOAA normal
Frost risk by date in Belcourt
Half of springs at Belcourt Keya Radio, ND see their last 32°F night by May 19; only one in ten is past it by May 5, and one in ten still has one after June 1. Planting tender crops after May 25 leaves a 30% risk of a frost on them, after May 28 20%, and after June 1 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 21% of the 33 North Dakota stations behind this site's ZIP pages.
In fall the first 32°F night comes by September 24 in half of years, as early as September 10 one year in ten, and holds off past October 5 one year in ten. A hard freeze of 28°F follows 8 days later, around October 2; in spring the one-in-ten date for 28°F is May 24, 8 days before the 32°F one. The freeze-free season lasts 126 days in a typical year, shorter than at 88% of the 33 North Dakota stations; it reaches 143 days one year in ten and falls short of 105 one year in ten. On average 209 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 11 days longer, to about May 30, and return around September 14. Severe cold of 16°F or below comes every winter, usually between October 30 and April 14.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 16 | May 20 | May 23 | May 27 | May 30 | Jun 1 | Jun 5 | Jun 10 | Jun 21 |
| 32°F | May 5 | May 10 | May 14 | May 16 | May 19 | May 21 | May 25 | May 28 | Jun 1 |
| 28°F | Apr 28 | May 1 | May 4 | May 6 | May 9 | May 12 | May 15 | May 19 | May 24 |
| 24°F | Apr 16 | Apr 22 | Apr 26 | Apr 30 | May 1 | May 4 | May 6 | May 10 | May 17 |
| 20°F | Apr 9 | Apr 13 | Apr 16 | Apr 19 | Apr 23 | Apr 26 | Apr 30 | May 2 | May 7 |
| 16°F | Apr 1 | Apr 5 | Apr 8 | Apr 11 | Apr 14 | Apr 17 | Apr 20 | Apr 23 | Apr 30 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 1 | Sep 5 | Sep 9 | Sep 12 | Sep 14 | Sep 17 | Sep 20 | Sep 23 | Sep 27 |
| 32°F | Sep 10 | Sep 14 | Sep 18 | Sep 21 | Sep 24 | Sep 26 | Sep 28 | Oct 1 | Oct 5 |
| 28°F | Sep 18 | Sep 24 | Sep 27 | Sep 29 | Oct 2 | Oct 4 | Oct 7 | Oct 11 | Oct 16 |
| 24°F | Sep 28 | Oct 1 | Oct 4 | Oct 8 | Oct 11 | Oct 14 | Oct 17 | Oct 20 | Oct 24 |
| 20°F | Oct 5 | Oct 10 | Oct 14 | Oct 17 | Oct 20 | Oct 23 | Oct 27 | Oct 30 | Nov 3 |
| 16°F | Oct 13 | Oct 19 | Oct 23 | Oct 27 | Oct 30 | Nov 1 | Nov 3 | Nov 7 | Nov 11 |
Freeze probabilities 1991–2020 at Belcourt Keya Radio, ND, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 58316 →Compare Belcourt with another place →
Weather by month in Belcourt
July is the warmest month at Belcourt Keya Radio, ND, averaging 79°F by day and 55°F at night; January is the coldest at 18°F and -5°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, June still brings one in 10% of years.
Warmth for growing adds up to 1,783 growing degree days a year (base 50°F), fewer than at 94% of the 33 North Dakota stations. 29% of them (515) have built up by the end of June, and July adds the most, 535.
| Month | High °F | Low °F | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|
| Jan | 18 | -5 | 100% | 31 | 0 |
| Feb | 22 | -2 | 100% | 28 | 0 |
| Mar | 34 | 12 | 100% | 30 | 1 |
| Apr | 50 | 26 | 100% | 23 | 19 |
| May | 64 | 40 | 98% | 9 | 143 |
| Jun | 73 | 50 | 10% | 1 | 352 |
| Jul | 79 | 55 | 0% | <1 | 535 |
| Aug | 79 | 53 | 1% | <1 | 490 |
| Sep | 69 | 43 | 78% | 5 | 210 |
| Oct | 53 | 30 | 100% | 21 | 32 |
| Nov | 35 | 16 | 100% | 29 | 0 |
| Dec | 22 | 2 | 100% | 31 | 0 |
Monthly normals 1991–2020 at Belcourt Keya Radio, ND (1,960 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
Compared with the next station
The nearest other station, Bottineau, ND, 31 miles west of Belcourt and 341 feet lower, has a last frost 4 days earlier (May 15), a first frost 1 day later (September 25), a season 7 days longer.
When it snows in Belcourt, North Dakota
The first measurable snow (0.1 inch or more) in Belcourt usually arrives around November 7, and the last of the season around March 31. Those are the middle dates across the winters of 1991–2020 at Belcourt Keya Radio, ND, 0.6 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 49 days after the last snow.
Planting calendar for 58316
| When | What to do |
|---|---|
| March 10 – March 24 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 24 – April 7 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 21 – May 5 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 19 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 2 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 10 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| September 24 onward | Plant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter. |
The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.
Where these figures come from
ZIP 58316 is under a mile from Belcourt Keya Radio, ND, which stands at 1,960 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 58316 in zone 3b, the band where the coldest night of the year averaged -35 to -30°F (-37.2 to -34.4°C) over 1991–2020; a zone describes winter lows, not frost dates.
Frost dates across North Dakota →
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.