USDA Hardiness Zone 4a
Frost Dates for 56547 — Glyndon, Minnesota
NOAA 1991–2020 normals from Moorhead, MN (904 ft), 9 miles west.
Updated
In Glyndon, the last spring frost (32°F) is around May 5 in half of years and has passed by May 20 in nine years out of ten. The first fall frost comes around October 3, as early as September 22 one year in ten, leaving a typical freeze-free season of 150 days (NOAA, Moorhead, MN).
- Last spring frost
- May 5
- First fall frost
- October 3
- Growing season
- 150 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 5
- Last snow
- April 12
- Winters with snow
- 100%
- Snow per year
- 52.7"
median, 1991–2020
median, 1991–2020
18 of 18 observed
NOAA normal
Frost risk by date in Glyndon
Half of springs at Moorhead, MN see their last 32°F night by May 5; only one in ten is past it by April 23, and one in ten still has one after May 20. Planting tender crops after May 11 leaves a 30% risk of a frost on them, after May 14 20%, and after May 20 10%. The 15 days between the even-odds date and the one-in-ten date is wider than at 64% of the 142 Minnesota stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 3 in half of years, as early as September 22 one year in ten, and holds off past October 18 one year in ten. A hard freeze of 28°F follows 11 days later, around October 14; in spring the one-in-ten date for 28°F is May 9, 11 days before the 32°F one. The freeze-free season lasts 150 days in a typical year, shorter than at 51% of the 142 Minnesota stations; it reaches 169 days one year in ten and falls short of 132 one year in ten. On average 170 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 15, and return around September 24. Severe cold of 16°F or below comes every winter, usually between November 9 and April 3.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 3 | May 7 | May 10 | May 13 | May 15 | May 18 | May 21 | May 24 | May 29 |
| 32°F | Apr 23 | Apr 28 | May 1 | May 3 | May 5 | May 8 | May 11 | May 14 | May 20 |
| 28°F | Apr 12 | Apr 18 | Apr 21 | Apr 24 | Apr 28 | Apr 30 | May 2 | May 5 | May 9 |
| 24°F | Apr 4 | Apr 8 | Apr 12 | Apr 14 | Apr 17 | Apr 20 | Apr 24 | Apr 28 | May 1 |
| 20°F | Mar 28 | Apr 1 | Apr 4 | Apr 6 | Apr 9 | Apr 12 | Apr 15 | Apr 18 | Apr 23 |
| 16°F | Mar 18 | Mar 25 | Mar 29 | Apr 1 | Apr 3 | Apr 5 | Apr 8 | Apr 12 | Apr 17 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 12 | Sep 17 | Sep 20 | Sep 22 | Sep 24 | Sep 26 | Sep 28 | Oct 1 | Oct 5 |
| 32°F | Sep 22 | Sep 25 | Sep 28 | Oct 1 | Oct 3 | Oct 6 | Oct 9 | Oct 13 | Oct 18 |
| 28°F | Oct 1 | Oct 4 | Oct 8 | Oct 11 | Oct 14 | Oct 18 | Oct 21 | Oct 24 | Oct 29 |
| 24°F | Oct 9 | Oct 14 | Oct 18 | Oct 21 | Oct 25 | Oct 28 | Oct 31 | Nov 3 | Nov 7 |
| 20°F | Oct 18 | Oct 24 | Oct 28 | Oct 31 | Nov 2 | Nov 4 | Nov 6 | Nov 10 | Nov 14 |
| 16°F | Oct 27 | Nov 1 | Nov 4 | Nov 6 | Nov 9 | Nov 11 | Nov 14 | Nov 18 | Nov 23 |
Freeze probabilities 1991–2020 at Moorhead, MN, 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 56547 →Compare Glyndon with another place →
Weather by month in Glyndon
July is the warmest month at Moorhead, MN, averaging 82°F by day and 61°F at night; January is the coldest at 17°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 72% of years.
Warmth for growing adds up to 2,453 growing degree days a year (base 50°F), more than at 52% of the 142 Minnesota stations. 33% of them (810) have built up by the end of June, and July adds the most, 659. Precipitation totals 26.0 inches a year, most in June (4.7") 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 | 17 | 0 | 0.7 | 100% | 31 | 0 |
| Feb | 23 | 4 | 0.7 | 100% | 27 | 0 |
| Mar | 37 | 18 | 1.3 | 100% | 26 | 4 |
| Apr | 54 | 32 | 1.7 | 100% | 15 | 42 |
| May | 69 | 45 | 3.4 | 72% | 2 | 251 |
| Jun | 78 | 56 | 4.7 | 0% | 0 | 513 |
| Jul | 82 | 61 | 3.4 | 0% | 0 | 659 |
| Aug | 81 | 59 | 2.7 | 0% | 0 | 604 |
| Sep | 72 | 49 | 2.9 | 40% | 1 | 315 |
| Oct | 55 | 36 | 2.5 | 99% | 11 | 63 |
| Nov | 38 | 21 | 1.1 | 100% | 26 | 1 |
| Dec | 23 | 8 | 0.9 | 100% | 31 | 0 |
Monthly normals 1991–2020 at Moorhead, MN (904 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, Fargo 3S, ND, 12 miles west of Glyndon, has a last frost 1 day earlier (May 4), a first frost 1 day earlier (October 2), a season 1 day longer.
When it snows in Glyndon, Minnesota
The first measurable snow (0.1 inch or more) in Glyndon usually arrives around November 5, and the last of the season around April 12. Those are the middle dates across the winters of 1991–2020 at Moorhead, MN, 8.8 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 23 days after the last snow.
Planting calendar for 56547
| When | What to do |
|---|---|
| February 24 – March 10 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 10 – March 24 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 7 – April 21 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 5 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 11 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 19 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 3 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 56547 is 9 miles from Moorhead, MN, which stands at 904 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station; its figures are presented in full for 56560 (Moorhead). The 2023 USDA Plant Hardiness Zone Map lists ZIP 56547 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 Minnesota →
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.