Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 30, 2026

Planting zone for Loretto, MN

Loretto, MN is in USDA zone 4b across its 2 ZIP codes. The median last spring frost is April 30 and the first fall frost October 8.

Loretto on the zone map

Outlined: its 1 ZIP code areas · 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.

Zone4b−25 to −20 °F

ZIP codes2

Last frostApr 30

First frostOct 8

Growing season159 days

4b 2 ZIPs

Frost forecast — next 7 nights

live from the National Weather Service

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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 Loretto, MN

JanFebMarAprMayJunJulAugSepOctNovDec

Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free

Last spring frostApril 30median — 50% chance of a later frost

Safe for tender plantsMay 14only 10% chance of frost after

First fall frostOctober 8median — 10% chance by Sep 24

Growing season159 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 22 and returns around October 19.

From the NOAA station Delano, MN, elevation 974 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 Loretto

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 19 – Apr 2

SpinachSow outdoors · Mar 19 – Apr 9

Broccoli, cabbageStart indoors · Feb 19 – Mar 5

Broccoli, cabbageTransplant · Apr 9 – Apr 23

Onion setsPlant outdoors · Apr 2 – Apr 16

PotatoesPlant outdoors · Apr 9 – Apr 23

LettuceSow outdoors · Apr 2 – Apr 16

Carrots, beetsSow outdoors · Apr 9 – Apr 23

TomatoesStart indoors · Mar 5 – Mar 19

TomatoesTransplant · May 7 – May 21

Peppers, eggplantStart indoors · Feb 19 – Mar 5

Peppers, eggplantTransplant · May 14 – May 28

BeansSow outdoors · May 7 – May 21

Sweet cornSow outdoors · May 7 – May 21

Cucumbers, squashSow outdoors · May 7 – May 21

Fall lettuce, spinachSow outdoors · Aug 13 – Aug 27

GarlicPlant cloves · Sep 24 – Oct 29

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 30) and first fall frost (Oct 8) 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 55357 came on Apr 11 — 7 days earlier than the 1991–2020 average (Apr 18).

average
Apr 182026
Apr 11

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 4b in Minnesota

497 plants native to the lower 48 states, recorded in Minnesota, and rated by the USDA to survive −25 °F or colder — the bottom of zone 4b. Each links to its USDA PLANTS profile.

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 Loretto, MN.

Soil in Loretto, MN

The soil mapped at the center of ZIP 55357 is Muskego — muck, very poorly drained.

TextureMucktop layer

DrainageVery poorly drainedconsider raised beds

Organic matter75%high

Hydrologic groupC/Dslow when drained; wet otherwise

Farmland classNot prime farmlandUSDA classification

Map unit: Muskego, Blue Earth, and Houghton soils, ponded, 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 55357; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Loretto, MN

Summer high83 °Faverage high, July

Winter low4 °Faverage low, January

Hot days8days a year at 90 °F or more

Freezing nights166nights a year at 32 °F or less

Growing degree days2,592base 50 °F — the season’s usable heat

Longest day15 h 37 mindaylight on June 21

Shortest day8 h 45 mindaylight on December 21

Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)

Precipitation30.6 inper year, rain and melted snow

Snowfall45 inper year

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Delano, MN (6 mi away); precipitation: Rockford, MN (3 mi away). Daylight is calculated from latitude.

ZIP codes in Loretto

Minnesota planting zones →

Questions about Loretto

What planting zone is Loretto, MN?

Loretto, MN is in USDA hardiness zone 4b on the 2023 map (4b: −25 to −20 °F).

When is the last frost in Loretto, MN?

The median last spring frost is April 30 and the median first fall frost is October 8 (NOAA 1991–2020 normals, Delano station).

When can I plant a garden in Loretto, MN?

Cool-season crops like peas and spinach go in around Mar 19 – Apr 9; tomatoes, peppers, beans and squash after about May 7, once frost risk has passed.

What kind of onions grow in Loretto, MN?

Long-day onions: the longest day is 15 h 37 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

How much rain and snow does Loretto, MN get?

About 30.6 inches of precipitation a year and 45 inches of snowfall (NOAA 1991–2020 normals).