USDA Hardiness Zone 4a
Frost Dates for 58784 — Stanley, North Dakota
NOAA 1991–2020 normals from Stanley 3 NNW, ND (2,280 ft), under a mile southeast.
Updated
In Stanley, the last spring frost (32°F) is around May 17 in half of years and has passed by May 29 in nine years out of ten. The first fall frost comes around September 23, as early as September 12 one year in ten, leaving a typical freeze-free season of 127 days (NOAA, Stanley 3 NNW, ND).
- Last spring frost
- May 17
- First fall frost
- September 23
- Growing season
- 127 days
- Hardiness zone
- 4a
50% probability
50% probability
freeze-free, 50%
-30 to -25°F (-34.4 to -31.7°C) coldest night
- First snow
- October 17
- Last snow
- April 28
- Winters with snow
- 100%
- Snow per year
- 47.4"
median, 1991–2020
median, 1991–2020
24 of 24 observed
NOAA normal
Frost risk by date in Stanley
Half of springs at Stanley 3 NNW, ND see their last 32°F night by May 17; only one in ten is past it by May 7, and one in ten still has one after May 29. Planting tender crops after May 22 leaves a 30% risk of a frost on them, after May 25 20%, and after May 29 10%. The 12 days between the even-odds date and the one-in-ten date is narrower than at 79% of the 33 North Dakota stations behind this site's ZIP pages.
In fall the first 32°F night comes by September 23 in half of years, as early as September 12 one year in ten, and holds off past October 3 one year in ten. A hard freeze of 28°F follows 7 days later, around September 30; in spring the one-in-ten date for 28°F is May 19, 10 days before the 32°F one. The freeze-free season lasts 127 days in a typical year, shorter than at 85% of the 33 North Dakota stations; it reaches 143 days one year in ten and falls short of 111 one year in ten. On average 202 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 10 days longer, to about May 27, and return around September 15. Severe cold of 16°F or below comes every winter, usually between October 29 and April 9.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 15 | May 18 | May 21 | May 24 | May 27 | May 29 | Jun 1 | Jun 3 | Jun 9 |
| 32°F | May 7 | May 10 | May 12 | May 14 | May 17 | May 19 | May 22 | May 25 | May 29 |
| 28°F | Apr 26 | May 1 | May 3 | May 6 | May 8 | May 10 | May 13 | May 15 | May 19 |
| 24°F | Apr 13 | Apr 18 | Apr 23 | Apr 27 | Apr 30 | May 2 | May 4 | May 7 | May 11 |
| 20°F | Apr 4 | Apr 9 | Apr 12 | Apr 15 | Apr 17 | Apr 20 | Apr 23 | Apr 27 | May 2 |
| 16°F | Mar 25 | Apr 1 | Apr 3 | Apr 6 | Apr 9 | Apr 12 | Apr 15 | Apr 18 | Apr 23 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 2 | Sep 7 | Sep 10 | Sep 13 | Sep 15 | Sep 17 | Sep 19 | Sep 22 | Sep 25 |
| 32°F | Sep 12 | Sep 16 | Sep 19 | Sep 21 | Sep 23 | Sep 25 | Sep 27 | Sep 30 | Oct 3 |
| 28°F | Sep 19 | Sep 22 | Sep 25 | Sep 27 | Sep 30 | Oct 3 | Oct 6 | Oct 10 | Oct 14 |
| 24°F | Sep 26 | Oct 1 | Oct 4 | Oct 7 | Oct 11 | Oct 13 | Oct 17 | Oct 20 | Oct 25 |
| 20°F | Oct 4 | Oct 11 | Oct 15 | Oct 17 | Oct 20 | Oct 23 | Oct 26 | Oct 29 | Nov 3 |
| 16°F | Oct 13 | Oct 19 | Oct 23 | Oct 26 | Oct 29 | Oct 31 | Nov 3 | Nov 6 | Nov 12 |
Freeze probabilities 1991–2020 at Stanley 3 NNW, 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 58784 →Compare Stanley with another place →
Weather by month in Stanley
July is the warmest month at Stanley 3 NNW, ND, averaging 80°F by day and 54°F at night; January is the coldest at 17°F and -1°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month.
Warmth for growing adds up to 1,768 growing degree days a year (base 50°F), fewer than at 97% of the 33 North Dakota stations. 28% of them (493) have built up by the end of June, and July adds the most, 521. Precipitation totals 19.2 inches a year, most in June (3.9") and least in January (0.5"); May to September bring 70% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 17 | -1 | 0.5 | 100% | 31 | 0 |
| Feb | 22 | 3 | 0.6 | 100% | 28 | 0 |
| Mar | 34 | 14 | 0.8 | 100% | 30 | 1 |
| Apr | 51 | 26 | 1.3 | 100% | 23 | 19 |
| May | 64 | 38 | 2.5 | 98% | 9 | 134 |
| Jun | 73 | 49 | 3.9 | 6% | <1 | 338 |
| Jul | 80 | 54 | 3.1 | 0% | 0 | 521 |
| Aug | 80 | 52 | 2.1 | 1% | 0 | 498 |
| Sep | 70 | 42 | 1.8 | 83% | 3 | 221 |
| Oct | 53 | 29 | 1.3 | 100% | 19 | 35 |
| Nov | 35 | 16 | 0.7 | 100% | 29 | 1 |
| Dec | 22 | 5 | 0.6 | 100% | 31 | 0 |
Monthly normals 1991–2020 at Stanley 3 NNW, ND (2,280 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, Tioga 1E, ND, 23 miles west of Stanley, has a last frost 6 days earlier (May 11), a first frost 3 days later (September 26), a season 9 days longer.
When it snows in Stanley, North Dakota
The first measurable snow (0.1 inch or more) in Stanley usually arrives around October 17, and the last of the season around April 28. Those are the middle dates across the winters of 1991–2020 at Stanley 3 NNW, ND, 0.9 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 19 days after the last snow.
Planting calendar for 58784
| When | What to do |
|---|---|
| March 8 – March 22 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 22 – April 5 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 19 – May 3 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 17 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 1 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 9 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| September 23 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 58784 is under a mile from Stanley 3 NNW, ND, which stands at 2,280 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 58784 in zone 4a, the band where the coldest night of the year averaged -30 to -25°F (-34.4 to -31.7°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.