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

Planting zone for 58365 — Rocklake, ND

ZIP code 58365 (Rocklake, Towner County) is in USDA zone 3b: the coldest winter night averages −35 to −30 °F. The median last spring frost is May 18 and the first fall frost September 23.

Where ZIP 58365 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 18
First frostSep 23
2012 zone3b

Same zone as on the 2012 map. 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 Rocklake, ND…

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 Rocklake, ND

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostMay 18median — 50% chance of a later frost
Safe for tender plantsMay 31only 10% chance of frost after
First fall frostSeptember 23median — 10% chance by Sep 11
Growing season127 daysfrost-free, median

A hard freeze (28 °F) usually ends around May 8 and returns around October 1.

From the NOAA station Hansboro 4 Nne, ND — 12 miles away, elevation 1,539 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 58365

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Apr 6 – Apr 20
SpinachSow outdoors · Apr 6 – Apr 27
Broccoli, cabbageStart indoors · Mar 9 – Mar 23
Broccoli, cabbageTransplant · Apr 27 – May 11
Onion setsPlant outdoors · Apr 20 – May 4
PotatoesPlant outdoors · Apr 27 – May 11
LettuceSow outdoors · Apr 20 – May 4
Carrots, beetsSow outdoors · Apr 27 – May 11
TomatoesStart indoors · Mar 23 – Apr 6
TomatoesTransplant · May 25 – Jun 8
Peppers, eggplantStart indoors · Mar 9 – Mar 23
Peppers, eggplantTransplant · Jun 1 – Jun 15
BeansSow outdoors · May 25 – Jun 8
Sweet cornSow outdoors · May 25 – Jun 8
Cucumbers, squashSow outdoors · May 25 – Jun 8
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 18) 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 58365 came on May 8 — 10 days later than the 1991–2020 average (Apr 28).

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 Rocklake, ND

The soil mapped at the center of ZIP 58365 is Hamerly — loam, somewhat poorly drained.

TextureLoama good balance for most vegetables
pH7.5slightly alkaline; most vegetables like 6.0–7.0
DrainageSomewhat poorly drainedconsider raised beds
Organic matter4%moderate
Hydrologic groupCwater soaks in slowly
Farmland classFarmland of statewide importanceUSDA classification

Map unit: Hamerly-Cresbard loams, 0 to 3 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 58365; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Rocklake, ND

Summer high81 °Faverage high, July
Winter low−5 °Faverage low, January
Hot days7days a year at 90 °F or more
Freezing nights203nights a year at 32 °F or less
Growing degree days1,904base 50 °F — the season’s usable heat
Longest day16 h 11 mindaylight on June 21
Shortest day8 h 15 mindaylight on December 21
Onions to growLong-daysummer days reach 15+ hours, enough for long-day varieties (intermediate types work too)
Precipitation19 inper year, rain and melted snow
Snowfall38 inper year

Average high and low, by month

−20°−10°0°10°20°30°40°50°60°70°80°90°32 °FJanuary: average high 17 °F, low -5 °F 17°−5° JanFebruary: average high 21 °F, low -2 °F 21°−2° FebMarch: average high 34 °F, low 12 °F 34°12° MarApril: average high 52 °F, low 27 °F 52°27° AprMay: average high 65 °F, low 40 °F 65°40° MayJune: average high 75 °F, low 51 °F 75°51° JunJuly: average high 81 °F, low 55 °F 81°55° JulAugust: average high 80 °F, low 52 °F 80°52° AugSeptember: average high 71 °F, low 43 °F 71°43° SepOctober: average high 54 °F, low 30 °F 54°30° OctNovember: average high 35 °F, low 14 °F 35°14° NovDecember: average high 22 °F, low 2 °F 22°2° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″January: 0.47 in precipitation, 5.7 in snowfall 0.5❄6 JanFebruary: 0.45 in precipitation, 5 in snowfall 0.5❄5 FebMarch: 0.92 in precipitation, 5.7 in snowfall 0.9❄6 MarApril: 0.98 in precipitation, 2.7 in snowfall 1.0❄3 AprMay: 2.68 in precipitation, 0.5 in snowfall 2.7❄1 MayJune: 3.71 in precipitation 3.7 JunJuly: 2.37 in precipitation 2.4 JulAugust: 2.91 in precipitation 2.9 AugSeptember: 1.76 in precipitation 1.8 SepOctober: 1.16 in precipitation, 2.2 in snowfall 1.2❄2 OctNovember: 0.77 in precipitation, 6.6 in snowfall 0.8❄7 NovDecember: 0.79 in precipitation, 9.2 in snowfall 0.8❄9 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Hansboro 4 Nne, ND (12 mi away); precipitation: Hansboro 4 Nne, ND (12 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 3b.

583393b
Hansboro, ND · 10 mi
583633b
Perth, ND · 12 mi
583723b
Sarles, ND · 12 mi
583233b
Calvin, ND · 14 mi
583673b
Rolla, ND · 15 mi
583313b
Egeland, ND · 15 mi
583173b
Bisbee, ND · 17 mi
583523b
Munich, ND · 20 mi

North Dakota planting zones →

Questions about 58365

What planting zone is ZIP code 58365?

ZIP code 58365 (Rocklake, ND) 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 Rocklake, ND?

The median last spring frost (32 °F) near 58365 is May 18; after May 31 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Hansboro 4 Nne station.

When is the first frost in Rocklake, ND?

The median first fall frost near 58365 is September 23, giving a median frost-free growing season of 127 days.

When should I plant tomatoes in 58365?

Start tomato seeds indoors around Mar 23 – Apr 6 and set transplants outside around May 25 – Jun 8, one to three weeks after the median last frost.

How much rain and snow does 58365 get?

About 19 inches of precipitation a year and 38 inches of snowfall (NOAA 1991–2020 normals, Hansboro 4 Nne station).

How hot do summers get in Rocklake, ND?

The average high peaks at 81 °F in July, with about 7 days a year at 90 °F or more.

What kind of soil does 58365 have?

The USDA soil survey maps Hamerly at the center of ZIP 58365: loam, somewhat poorly drained, pH about 7.5 (slightly alkaline).

Did spring come early in Rocklake, ND in 2026?

Spring leaf-out near 58365 came on May 8 in 2026, 10 days later than the 1991–2020 average (Apr 28), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Rocklake, ND?

Long-day onions: the longest day near 58365 is 16 h 11 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).