USDA Hardiness Zone 4a
Frost Dates for 58341 — Harvey, North Dakota
NOAA 1991–2020 normals from Harvey 4NE, ND (1,611 ft), 3 miles northwest.
Updated
In Harvey, the last spring frost (32°F) is around May 12 in half of years and has passed by May 25 in nine years out of ten. The first fall frost comes around September 26, as early as September 14 one year in ten, leaving a typical freeze-free season of 135 days (NOAA, Harvey 4NE, ND).
- Last spring frost
- May 12
- First fall frost
- September 26
- Growing season
- 135 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
- November 4
- Last snow
- April 4
- Winters with snow
- 100%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
15 of 15 observed
NOAA normal
Frost risk by date in Harvey
Half of springs at Harvey 4NE, ND see their last 32°F night by May 12; only one in ten is past it by April 30, and one in ten still has one after May 25. Planting tender crops after May 17 leaves a 30% risk of a frost on them, after May 21 20%, and after May 25 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 26 in half of years, as early as September 14 one year in ten, and holds off past October 6 one year in ten. A hard freeze of 28°F follows 8 days later, around October 4; in spring the one-in-ten date for 28°F is May 18, 7 days before the 32°F one. The freeze-free season lasts 135 days in a typical year, shorter than at 70% of the 33 North Dakota stations; it reaches 152 days one year in ten and falls short of 119 one year in ten. On average 189 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 22, and return around September 18. Severe cold of 16°F or below comes every winter, usually between October 29 and April 7.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 9 | May 13 | May 16 | May 19 | May 22 | May 25 | May 27 | May 30 | Jun 1 |
| 32°F | Apr 30 | May 4 | May 7 | May 9 | May 12 | May 14 | May 17 | May 21 | May 25 |
| 28°F | Apr 18 | Apr 24 | Apr 28 | May 1 | May 4 | May 6 | May 10 | May 13 | May 18 |
| 24°F | Apr 10 | Apr 15 | Apr 18 | Apr 21 | Apr 25 | Apr 28 | Apr 30 | May 4 | May 9 |
| 20°F | Apr 2 | Apr 6 | Apr 8 | Apr 11 | Apr 14 | Apr 17 | Apr 20 | Apr 25 | Apr 30 |
| 16°F | Mar 24 | Mar 31 | Apr 2 | Apr 5 | Apr 7 | Apr 9 | Apr 13 | Apr 16 | Apr 22 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 5 | Sep 9 | Sep 12 | Sep 15 | Sep 18 | Sep 20 | Sep 22 | Sep 24 | Sep 28 |
| 32°F | Sep 14 | Sep 18 | Sep 21 | Sep 24 | Sep 26 | Sep 28 | Oct 1 | Oct 3 | Oct 6 |
| 28°F | Sep 23 | Sep 27 | Sep 29 | Oct 2 | Oct 4 | Oct 6 | Oct 9 | Oct 11 | Oct 15 |
| 24°F | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 12 | Oct 15 | Oct 18 | Oct 20 | Oct 24 |
| 20°F | Oct 8 | Oct 12 | Oct 16 | Oct 18 | Oct 21 | Oct 24 | Oct 26 | Oct 29 | Nov 2 |
| 16°F | Oct 17 | Oct 21 | Oct 24 | Oct 27 | Oct 29 | Nov 1 | Nov 4 | Nov 7 | Nov 11 |
Freeze probabilities 1991–2020 at Harvey 4NE, 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 58341 →Compare Harvey with another place →
Weather by month in Harvey
July is the warmest month at Harvey 4NE, ND, averaging 81°F by day and 57°F at night; January is the coldest at 17°F and -2°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 87% of years.
Warmth for growing adds up to 2,035 growing degree days a year (base 50°F), fewer than at 64% of the 33 North Dakota stations. 32% of them (641) have built up by the end of June, and July adds the most, 580.
| Month | High °F | Low °F | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|
| Jan | 17 | -2 | 100% | 31 | 0 |
| Feb | 22 | 2 | 100% | 28 | 0 |
| Mar | 35 | 15 | 100% | 29 | 1 |
| Apr | 52 | 29 | 100% | 19 | 27 |
| May | 66 | 42 | 87% | 5 | 192 |
| Jun | 75 | 53 | 0% | 0 | 421 |
| Jul | 81 | 57 | 0% | 0 | 580 |
| Aug | 80 | 54 | 0% | 0 | 516 |
| Sep | 71 | 45 | 70% | 2 | 253 |
| Oct | 54 | 31 | 100% | 17 | 44 |
| Nov | 36 | 16 | 100% | 28 | 2 |
| Dec | 22 | 4 | 100% | 31 | 0 |
Monthly normals 1991–2020 at Harvey 4NE, ND (1,611 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, Carrington, ND, 40 miles southeast of Harvey, has a last frost 2 days earlier (May 10), a first frost 2 days later (September 28), a season 4 days longer.
When it snows in Harvey, North Dakota
The first measurable snow (0.1 inch or more) in Harvey usually arrives around November 4, and the last of the season around April 4. Those are the middle dates across the winters of 1991–2020 at Harvey 4NE, ND, 3.2 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 38 days after the last snow.
Planting calendar for 58341
| When | What to do |
|---|---|
| March 3 – March 17 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 17 – March 31 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 14 – April 28 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 12 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 4 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 12 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| September 26 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 58341 is 3 miles from Harvey 4NE, ND, which stands at 1,611 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 58341 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.