Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated

Planting zone for 56720 — Donaldson, MN

ZIP code 56720 (Donaldson, Kittson County) is in USDA zone 4a: the coldest winter night averages −30 to −25 °F. The median last spring frost is May 8 and the first fall frost September 30.

Where ZIP 56720 is

Outlined: the ZIP code area · tap the map for the zone at any spot · scroll or pinch to zoom

Not the official USDA Plant Hardiness Zone Map. Zones come from the 2023 USDA hardiness-zone data by the PRISM Group, Oregon State University; we re-mapped and recolored them. The official map is at planthardiness.ars.usda.gov.

Zone4a−30 to −25 °F
Coldest night−34.4 to −31.7 °C
Last frostMay 8
First frostSep 30
2012 zone3b

Was 3b on the 2012 map — half a zone warmer now. The zone is the one at the center of the ZIP code; hilly ZIPs can span two zones. What zone 4a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Donaldson, MN…

Forecast data: National Weather Service (api.weather.gov), public domain. This is not a warning service — for official frost and freeze warnings see weather.gov.

Frost dates in Donaldson, MN

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 8median — 50% chance of a later frost
Safe for tender plantsMay 24only 10% chance of frost after
First fall frostSeptember 30median — 10% chance by Sep 16
Growing season142 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 30 and returns around October 6.

From the NOAA station Hallock, MN — 14 miles away, elevation 814 ft. NOAA NCEI U.S. Climate Normals 1991–2020, 32 °F threshold. Low spots and valleys can freeze later in spring than the station.

When to plant vegetables in 56720

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Mar 27 – Apr 10
SpinachSow outdoors · Mar 27 – Apr 17
Broccoli, cabbageStart indoors · Feb 27 – Mar 13
Broccoli, cabbageTransplant · Apr 17 – May 1
Onion setsPlant outdoors · Apr 10 – Apr 24
PotatoesPlant outdoors · Apr 17 – May 1
LettuceSow outdoors · Apr 10 – Apr 24
Carrots, beetsSow outdoors · Apr 17 – May 1
TomatoesStart indoors · Mar 13 – Mar 27
TomatoesTransplant · May 15 – May 29
Peppers, eggplantStart indoors · Feb 27 – Mar 13
Peppers, eggplantTransplant · May 22 – Jun 5
BeansSow outdoors · May 15 – May 29
Sweet cornSow outdoors · May 15 – May 29
Cucumbers, squashSow outdoors · May 15 – May 29
Fall lettuce, spinachSow outdoors · Aug 5 – Aug 19
GarlicPlant cloves · Sep 16 – Oct 21
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 8) and first fall frost (Sep 30) with the rules of thumb U.S. extension services publish. Cool-season crops take a light frost; warm-season crops do best once the soil is above about 60 °F.

When spring arrived in 2026

In 2026, spring leaf-out near 56720 came on May 4 — 8 days later than the 1991–2020 average (Apr 26).

JanFebMarAprMayJun

The Spring Index marks the day when accumulated warmth is enough for lilac and honeysuckle to leaf out — a widely used signal that the growing season has started. Source: USA National Phenology Network, www.usanpn.org — Spring Indices, first leaf, 2026 (data as of 2026-09-08) and 30-year average 1991–2020 (CC BY 4.0).

Native plants for zone 4a in Minnesota

445 plants native to the lower 48 states, recorded in Minnesota, and rated by the USDA to survive −30 °F or colder — the bottom of zone 4a. Each links to its USDA PLANTS profile.

Trees 45

American basswood100 ft · blooms late spring · low shade tolerance · to −46 °FAmerican beech80 ft · blooms mid spring · low shade tolerance · to −44 °FAmerican elm120 ft · blooms early spring · medium shade tolerance · to −46 °Farborvitae50 ft · blooms mid spring · medium shade tolerance · to −33 °Fbalsam fir60 ft · blooms mid summer · low shade tolerance · to −43 °Fbalsam poplar80 ft · blooms late spring · high shade tolerance · to −79 °F

Shrubs 77

alderleaf buckthorn3 ft · blooms late spring · low shade tolerance · to −33 °FAllegheny serviceberry35 ft · blooms early spring · low shade tolerance · to −38 °Falternateleaf dogwood25 ft · blooms mid spring · low shade tolerance · to −47 °FAmerican black currant3 ft · blooms early spring · to −46 °FAmerican hazelnut10 ft · blooms spring · medium shade tolerance · to −33 °FAmerican hornbeam30 ft · blooms mid spring · low shade tolerance · to −34 °F

Wildflowers & perennials 173

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine bistort1 ft · blooms mid spring · high shade tolerance · to −38 °FAmerican bur-reed3 ft · blooms indeterminate · medium shade tolerance · to −33 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °FAmerican licorice4 ft · blooms late spring · medium shade tolerance · to −38 °FAmerican lotus3 ft · blooms mid summer · high shade tolerance · to −36 °F

Grasses 140

alkali cordgrass3 ft · blooms late summer · high shade tolerance · to −38 °Farctic brome3 ft · blooms early summer · low shade tolerance · to −33 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °Fbasin wildrye5 ft · blooms early spring · high shade tolerance · to −43 °Fbeaked sedge4 ft · blooms late spring · low shade tolerance · to −38 °FBebb's sedge3 ft · blooms late spring · low shade tolerance · to −38 °F

Vines 3

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °F

Source: USDA, NRCS. 2026. The PLANTS Database (plants.usda.gov), National Plant Data Team — state distribution, native status and the “Temperature, Minimum” characteristic. Check light, moisture and soil needs before buying; local nurseries and your state native plant society can confirm what thrives in Donaldson, MN.

Soil in Donaldson, MN

The soil mapped at the center of ZIP 56720 is Northcote — clay, poorly drained.

TextureClayholds water and nutrients; slow to drain and warm up
pH7.4slightly alkaline; most vegetables like 6.0–7.0
DrainagePoorly drainedconsider raised beds
Organic matter5%high
Hydrologic groupDwater soaks in very slowly
Farmland classPrime farmland if drainedUSDA classification

Map unit: Northcote clay, 0 to 1 percent slopes.

Soil Survey Staff, Natural Resources Conservation Service, USDA. Soil Survey Geographic (SSURGO) Database, via Soil Data Access, accessed 2026-10-29. The soil at the center point of ZIP 56720; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Donaldson, MN

Summer high79 °Faverage high, July
Winter low−4 °Faverage low, January
Hot days7days a year at 90 °F or more
Freezing nights186nights a year at 32 °F or less
Growing degree days2,061base 50 °F — the season’s usable heat
Longest day16 h 08 mindaylight on June 21
Shortest day8 h 17 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation22.3 inper year, rain and melted snow

Average high and low, by month

−10°0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 13 °F, low -4 °F 13°−4° JanFebruary: average high 18 °F, low 0 °F 18°0° FebMarch: average high 32 °F, low 16 °F 32°16° MarApril: average high 50 °F, low 30 °F 50°30° AprMay: average high 66 °F, low 43 °F 66°43° MayJune: average high 76 °F, low 54 °F 76°54° JunJuly: average high 79 °F, low 57 °F 79°57° JulAugust: average high 79 °F, low 56 °F 79°56° AugSeptember: average high 69 °F, low 46 °F 69°46° SepOctober: average high 52 °F, low 33 °F 52°33° OctNovember: average high 34 °F, low 19 °F 34°19° NovDecember: average high 19 °F, low 5 °F 19°5° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 0.53 in precipitation 0.5 JanFebruary: 0.47 in precipitation 0.5 FebMarch: 0.72 in precipitation 0.7 MarApril: 1.14 in precipitation 1.1 AprMay: 3.00 in precipitation 3.0 MayJune: 4.24 in precipitation 4.2 JunJuly: 3.49 in precipitation 3.5 JulAugust: 2.58 in precipitation 2.6 AugSeptember: 2.57 in precipitation 2.6 SepOctober: 1.85 in precipitation 1.9 OctNovember: 0.93 in precipitation 0.9 NovDecember: 0.79 in precipitation 0.8 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Hallock, MN (14 mi away); precipitation: Hallock, MN (14 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

4 of the 8 nearest ZIP codes are in a different zone — elevation and distance from water change winter lows quickly.

567334a
Kennedy, MN · 5 mi
567574a
Stephen, MN · 6 mi
582254a
Drayton, ND · 15 mi
567134a
Argyle, MN · 15 mi
567283b
Hallock, MN · 16 mi
567293b
Halma, MN · 16 mi
567583b
Strandquist, MN · 18 mi
567343b
Lake Bronson, MN · 20 mi

Minnesota planting zones →

Questions about 56720

What planting zone is ZIP code 56720?

ZIP code 56720 (Donaldson, MN) is in USDA hardiness zone 4a on the 2023 map: the coldest night of an average winter reaches −30 to −25 °F (−34.4 to −31.7 °C).

When is the last frost in Donaldson, MN?

The median last spring frost (32 °F) near 56720 is May 8; after May 24 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Hallock station.

When is the first frost in Donaldson, MN?

The median first fall frost near 56720 is September 30, giving a median frost-free growing season of 142 days.

When should I plant tomatoes in 56720?

Start tomato seeds indoors around Mar 13 – Mar 27 and set transplants outside around May 15 – May 29, one to three weeks after the median last frost.

How much rain and snow does 56720 get?

About 22.3 inches of precipitation a year (NOAA 1991–2020 normals, Hallock station).

How hot do summers get in Donaldson, MN?

The average high peaks at 79 °F in July, with about 7 days a year at 90 °F or more.

What kind of soil does 56720 have?

The USDA soil survey maps Northcote at the center of ZIP 56720: clay, poorly drained, pH about 7.4 (slightly alkaline).

Did spring come early in Donaldson, MN in 2026?

Spring leaf-out near 56720 came on May 4 in 2026, 8 days later than the 1991–2020 average (Apr 26), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Donaldson, MN?

Long-day onions: the longest day near 56720 is 16 h 08 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 56720 change?

Yes. The 2012 USDA map put 56720 in zone 3b; the 2023 map puts it in zone 4a. The newer map uses 1991–2020 data and more weather stations.