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

Planting zone for 55616 — Two Harbors, MN

ZIP code 55616 (Two Harbors, Lake County) is in USDA zone 3b: the coldest winter night averages −35 to −30 °F. The median last spring frost is May 27 and the first fall frost September 23.

Where ZIP 55616 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.

Zone3b−35 to −30 °F
Coldest night−37.2 to −34.4 °C
Last frostMay 27
First frostSep 23
2012 zone4b

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

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Two Harbors, 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 Two Harbors, MN

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 27median — 50% chance of a later frost
Safe for tender plantsJune 10only 10% chance of frost after
First fall frostSeptember 23median — 10% chance by Sep 7
Growing season117 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 12 and returns around October 5.

From the NOAA station Two Harbors 7nw, MN — 9 miles away, elevation 1,355 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 55616

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 15 – Apr 29
SpinachSow outdoors · Apr 15 – May 6
Broccoli, cabbageStart indoors · Mar 18 – Apr 1
Broccoli, cabbageTransplant · May 6 – May 20
Onion setsPlant outdoors · Apr 29 – May 13
PotatoesPlant outdoors · May 6 – May 20
LettuceSow outdoors · Apr 29 – May 13
Carrots, beetsSow outdoors · May 6 – May 20
TomatoesStart indoors · Apr 1 – Apr 15
TomatoesTransplant · Jun 3 – Jun 17
Peppers, eggplantStart indoors · Mar 18 – Apr 1
Peppers, eggplantTransplant · Jun 10 – Jun 24
BeansSow outdoors · Jun 3 – Jun 17
Sweet cornSow outdoors · Jun 3 – Jun 17
Cucumbers, squashSow outdoors · Jun 3 – Jun 17
Fall lettuce, spinachSow outdoors · Jul 29 – Aug 12
GarlicPlant cloves · Sep 9 – Oct 14
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (May 27) and first fall frost (Sep 23) 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 55616 came on May 4 — 3 days later than the 1991–2020 average (May 1).

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 Two Harbors, MN

The soil mapped at the center of ZIP 55616 is Ahmeek — silt loam, well drained.

TextureSilt loama good balance for most vegetables
pH5.6moderately acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter5%high
Hydrologic groupCwater soaks in slowly
Farmland classNot prime farmlandUSDA classification

Map unit: Ahmeek-Aldenlake complex, 18 to 35 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 55616; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Two Harbors, MN

Summer high76 °Faverage high, July
Winter low−4 °Faverage low, January
Hot days2days a year at 90 °F or more
Freezing nights219nights a year at 32 °F or less
Growing degree days1,320base 50 °F — the season’s usable heat
Longest day15 h 56 mindaylight on June 21
Shortest day8 h 28 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation31.7 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 18 °F, low -4 °F 18°−4° JanFebruary: average high 23 °F, low -2 °F 23°−2° FebMarch: average high 36 °F, low 11 °F 36°11° MarApril: average high 48 °F, low 24 °F 48°24° AprMay: average high 63 °F, low 36 °F 63°36° MayJune: average high 72 °F, low 46 °F 72°46° JunJuly: average high 76 °F, low 50 °F 76°50° JulAugust: average high 74 °F, low 48 °F 74°48° AugSeptember: average high 66 °F, low 41 °F 66°41° SepOctober: average high 50 °F, low 31 °F 50°31° OctNovember: average high 34 °F, low 18 °F 34°18° NovDecember: average high 22 °F, low 4 °F 22°4° Dec

Precipitation by month inches

0″1″2″3″4″5″January: 1.13 in precipitation 1.1 JanFebruary: 1.07 in precipitation 1.1 FebMarch: 1.52 in precipitation 1.5 MarApril: 2.56 in precipitation 2.6 AprMay: 3.29 in precipitation 3.3 MayJune: 4.46 in precipitation 4.5 JunJuly: 3.88 in precipitation 3.9 JulAugust: 3.51 in precipitation 3.5 AugSeptember: 3.65 in precipitation 3.6 SepOctober: 3.06 in precipitation 3.1 OctNovember: 1.97 in precipitation 2.0 NovDecember: 1.64 in precipitation 1.6 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Brimson 2s, MN (8 mi away); precipitation: Two Harbors 9.7 Nne, MN (7 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

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

556023b
Brimson, MN · 12 mi
556014a
Beaver Bay, MN · 15 mi
556144a
Silver Bay, MN · 16 mi
556094b
Knife River, MN · 20 mi
557503b
Hoyt Lakes, MN · 23 mi
558034a
Duluth, MN · 23 mi
558044b
Duluth, MN · 25 mi
557633b
Makinen, MN · 26 mi

Minnesota planting zones →

Questions about 55616

What planting zone is ZIP code 55616?

ZIP code 55616 (Two Harbors, MN) is in USDA hardiness zone 3b on the 2023 map: the coldest night of an average winter reaches −35 to −30 °F (−37.2 to −34.4 °C).

When is the last frost in Two Harbors, MN?

The median last spring frost (32 °F) near 55616 is May 27; after June 10 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Two Harbors 7nw station.

When is the first frost in Two Harbors, MN?

The median first fall frost near 55616 is September 23, giving a median frost-free growing season of 117 days.

When should I plant tomatoes in 55616?

Start tomato seeds indoors around Apr 1 – Apr 15 and set transplants outside around Jun 3 – Jun 17, one to three weeks after the median last frost.

How much rain and snow does 55616 get?

About 31.7 inches of precipitation a year (NOAA 1991–2020 normals, Two Harbors 9.7 Nne station).

How hot do summers get in Two Harbors, MN?

The average high peaks at 76 °F in July, with about 2 days a year at 90 °F or more.

What kind of soil does 55616 have?

The USDA soil survey maps Ahmeek at the center of ZIP 55616: silt loam, well drained, pH about 5.6 (moderately acidic).

Did spring come early in Two Harbors, MN in 2026?

Spring leaf-out near 55616 came on May 4 in 2026, 3 days later than the 1991–2020 average (May 1), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Two Harbors, MN?

Long-day onions: the longest day near 55616 is 15 h 56 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 55616 change?

Yes. The 2012 USDA map put 55616 in zone 4b; the 2023 map puts it in zone 3b. The newer map uses 1991–2020 data and more weather stations.