USDA Hardiness Zone 4a
Frost Dates for 58102 — Fargo, North Dakota
NOAA 1991–2020 normals from Fargo Hector International Airport, ND (900 ft), 2 miles north.
Updated
In Fargo, the last spring frost (32°F) is around May 10 in half of years and has passed by May 23 in nine years out of ten. The first fall frost comes around September 30, as early as September 18 one year in ten, leaving a typical freeze-free season of 143 days (NOAA, Fargo Hector International Airport, ND).
- Last spring frost
- May 10
- First fall frost
- September 30
- Growing season
- 143 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 30
- Last snow
- April 12
- Winters with snow
- 100%
- Snow per year
- 51.4"
median, 1991–2020
median, 1991–2020
30 of 30 observed
NOAA normal
Frost risk by date in Fargo
Half of springs at Fargo Hector International Airport, ND see their last 32°F night by May 10; only one in ten is past it by April 27, and one in ten still has one after May 23. Planting tender crops after May 15 leaves a 30% risk of a frost on them, after May 18 20%, and after May 23 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 30 in half of years, as early as September 18 one year in ten, and holds off past October 15 one year in ten. A hard freeze of 28°F follows 10 days later, around October 10; in spring the one-in-ten date for 28°F is May 15, 8 days before the 32°F one. The freeze-free season lasts 143 days in a typical year, longer than at 73% of the 33 North Dakota stations; it reaches 162 days one year in ten and falls short of 124 one year in ten. On average 172 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 9 days longer, to about May 19, and return around September 22. Severe cold of 16°F or below comes every winter, usually between November 5 and April 4.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 6 | May 10 | May 14 | May 16 | May 19 | May 22 | May 25 | May 28 | Jun 2 |
| 32°F | Apr 27 | May 1 | May 4 | May 7 | May 10 | May 12 | May 15 | May 18 | May 23 |
| 28°F | Apr 15 | Apr 20 | Apr 25 | Apr 29 | Apr 30 | May 3 | May 6 | May 9 | May 15 |
| 24°F | Apr 5 | Apr 10 | Apr 13 | Apr 17 | Apr 20 | Apr 23 | Apr 27 | Apr 30 | May 5 |
| 20°F | Mar 28 | Apr 2 | Apr 5 | Apr 7 | Apr 11 | Apr 14 | Apr 17 | Apr 20 | Apr 25 |
| 16°F | Mar 18 | Mar 25 | Mar 29 | Apr 1 | Apr 4 | Apr 6 | Apr 9 | Apr 13 | Apr 18 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 9 | Sep 14 | Sep 18 | Sep 20 | Sep 22 | Sep 24 | Sep 27 | Sep 29 | Oct 3 |
| 32°F | Sep 18 | Sep 22 | Sep 25 | Sep 28 | Sep 30 | Oct 3 | Oct 5 | Oct 9 | Oct 15 |
| 28°F | Sep 26 | Sep 30 | Oct 4 | Oct 7 | Oct 10 | Oct 13 | Oct 17 | Oct 21 | Oct 26 |
| 24°F | Oct 4 | Oct 10 | Oct 14 | Oct 17 | Oct 21 | Oct 24 | Oct 27 | Oct 31 | Nov 3 |
| 20°F | Oct 15 | Oct 21 | Oct 25 | Oct 28 | Oct 31 | Nov 2 | Nov 4 | Nov 8 | Nov 12 |
| 16°F | Oct 23 | Oct 29 | Nov 1 | Nov 3 | Nov 5 | Nov 8 | Nov 12 | Nov 15 | Nov 20 |
Freeze probabilities 1991–2020 at Fargo Hector International Airport, 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 58102 →Compare Fargo with another place →
Weather by month in Fargo
July is the warmest month at Fargo Hector International Airport, ND, averaging 82°F by day and 59°F at night; January is the coldest at 18°F and 0°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 81% of years.
Warmth for growing adds up to 2,416 growing degree days a year (base 50°F), more than at 88% of the 33 North Dakota stations. 33% of them (802) have built up by the end of June, and July adds the most, 643. Precipitation totals 24.1 inches a year, most in June (4.3") and least in January (0.7"); May to September bring 66% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 18 | 0 | 0.7 | 100% | 31 | 0 |
| Feb | 23 | 4 | 0.7 | 100% | 27 | 0 |
| Mar | 36 | 18 | 1.3 | 100% | 27 | 4 |
| Apr | 54 | 32 | 1.5 | 100% | 16 | 45 |
| May | 69 | 44 | 3.1 | 81% | 3 | 247 |
| Jun | 78 | 56 | 4.3 | 1% | 0 | 506 |
| Jul | 82 | 59 | 3.1 | 0% | 0 | 643 |
| Aug | 81 | 57 | 2.6 | 0% | 0 | 581 |
| Sep | 72 | 48 | 2.7 | 51% | 1 | 318 |
| Oct | 56 | 35 | 2.2 | 100% | 12 | 69 |
| Nov | 38 | 21 | 1.0 | 100% | 26 | 3 |
| Dec | 24 | 8 | 0.9 | 100% | 31 | 0 |
Monthly normals 1991–2020 at Fargo Hector International Airport, ND (900 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, Moorhead, MN, 3 miles east of Fargo, has a last frost 5 days earlier (May 5), a first frost 3 days later (October 3), a season 7 days longer.
When it snows in Fargo, North Dakota
The first measurable snow (0.1 inch or more) in Fargo usually arrives around October 30, and the last of the season around April 12. Those are the middle dates across the winters of 1991–2020 at Fargo Hector International Airport, ND, 1.8 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 28 days after the last snow.
Planting calendar for 58102
| When | What to do |
|---|---|
| March 1 – March 15 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 15 – March 29 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 12 – April 26 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 10 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 8 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 16 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| September 30 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 58102 is 2 miles from Fargo Hector International Airport, ND, which stands at 900 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 58078 (West Fargo). The 2023 USDA Plant Hardiness Zone Map lists ZIP 58102 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.