Data: 2023 USDA zones (PRISM/OSU) · NOAA 1991–2020 normals · updated Oct 29, 2026

Planting zone for 55988 — Stockton, MN

ZIP code 55988 (Stockton, Winona County) is in USDA zone 5a: the coldest winter night averages −20 to −15 °F. The median last spring frost is April 23 and the first fall frost October 21.

Where ZIP 55988 is

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.

Zone5a−20 to −15 °F

Coldest night−28.9 to −26.1 °C

Last frostApr 23

First frostOct 21

2012 zone4b

Was 4b 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 5a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Stockton, 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 Stockton, MN

JanFebMarAprMayJunJulAugSepOctNovDec

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

Last spring frostApril 23median — 50% chance of a later frost

Safe for tender plantsMay 6only 10% chance of frost after

First fall frostOctober 21median — 10% chance by Oct 7

Growing season180 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 11 and returns around November 1.

From the NOAA station Winona Dam 5 A, MN — 7 miles away, elevation 663 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 55988

JanFebMarAprMayJunJulAugSepOctNovDec

PeasSow outdoors · Mar 12 – Mar 26

SpinachSow outdoors · Mar 12 – Apr 2

Broccoli, cabbageStart indoors · Feb 12 – Feb 26

Broccoli, cabbageTransplant · Apr 2 – Apr 16

Onion setsPlant outdoors · Mar 26 – Apr 9

PotatoesPlant outdoors · Apr 2 – Apr 16

LettuceSow outdoors · Mar 26 – Apr 9

Carrots, beetsSow outdoors · Apr 2 – Apr 16

TomatoesStart indoors · Feb 26 – Mar 12

TomatoesTransplant · Apr 30 – May 14

Peppers, eggplantStart indoors · Feb 12 – Feb 26

Peppers, eggplantTransplant · May 7 – May 21

BeansSow outdoors · Apr 30 – May 14

Sweet cornSow outdoors · Apr 30 – May 14

Cucumbers, squashSow outdoors · Apr 30 – May 14

Fall lettuce, spinachSow outdoors · Aug 26 – Sep 9

GarlicPlant cloves · Oct 7 – Nov 11

Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 23) and first fall frost (Oct 21) 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 55988 came on Mar 30 — 16 days earlier than the 1991–2020 average (Apr 15).

average
Apr 152026
Mar 30

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).

Soil in Stockton, MN

The soil mapped at the center of ZIP 55988 is Newalbin — silt loam, poorly drained.

TextureSilt loama good balance for most vegetables

pH6.7neutral; most vegetables like 6.0–7.0

DrainagePoorly drainedconsider raised beds

Organic matter2%moderate

Hydrologic groupB/Dmoderate when drained; wet otherwise

Farmland classPrime farmland if drainedUSDA classification

Map unit: Newalbin silt loam.

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 55988; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Stockton, MN

Summer high83 °Faverage high, July

Winter low8 °Faverage low, January

Hot days12days a year at 90 °F or more

Freezing nights148nights a year at 32 °F or less

Growing degree days2,817base 50 °F — the season’s usable heat

Longest day15 h 29 mindaylight on June 21

Shortest day8 h 53 mindaylight on December 21

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

Precipitation34.4 inper year, rain and melted snow

Snowfall38 inper year; 86 days with snow on the ground

Average high and low, by month

Precipitation by month inches · ❄ = snowfall

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Winona Dam 5 A, MN (7 mi away); precipitation: Winona Dam 5 A, MN (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

559425a

Homer, MN · 4 mi

559594b

Minnesota City, MN · 7 mi

559694b

Rollingstone, MN · 7 mi

Fountain City, WI · 12 mi

559104b

Altura, MN · 12 mi

Minnesota planting zones →

Questions about 55988

What planting zone is ZIP code 55988?

ZIP code 55988 (Stockton, MN) is in USDA hardiness zone 5a on the 2023 map: the coldest night of an average winter reaches −20 to −15 °F (−28.9 to −26.1 °C).

When is the last frost in Stockton, MN?

The median last spring frost (32 °F) near 55988 is April 23; after May 6 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Winona Dam 5 A station.

When is the first frost in Stockton, MN?

The median first fall frost near 55988 is October 21, giving a median frost-free growing season of 180 days.

When should I plant tomatoes in 55988?

Start tomato seeds indoors around Feb 26 – Mar 12 and set transplants outside around Apr 30 – May 14, one to three weeks after the median last frost.

How much rain and snow does 55988 get?

About 34.4 inches of precipitation a year and 38 inches of snowfall (NOAA 1991–2020 normals, Winona Dam 5 A station).

How hot do summers get in Stockton, MN?

The average high peaks at 83 °F in July, with about 12 days a year at 90 °F or more.

What kind of soil does 55988 have?

The USDA soil survey maps Newalbin at the center of ZIP 55988: silt loam, poorly drained, pH about 6.7 (neutral).

Did spring come early in Stockton, MN in 2026?

Spring leaf-out near 55988 came on Mar 30 in 2026, 16 days earlier than the 1991–2020 average (Apr 15), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Stockton, MN?

Long-day onions: the longest day near 55988 is 15 h 29 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 55988 change?

Yes. The 2012 USDA map put 55988 in zone 4b; the 2023 map puts it in zone 5a. The newer map uses 1991–2020 data and more weather stations.