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

Planting zone for 68358 — Firth, NE

ZIP code 68358 (Firth, Lancaster County) is in USDA zone 6a: the coldest winter night averages −10 to −5 °F. The median last spring frost is April 23 and the first fall frost October 12.

Where ZIP 68358 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.

Zone6a−10 to −5 °F
Coldest night−23.3 to −20.6 °C
Last frostApr 23
First frostOct 12
2012 zone5b

Was 5b 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 6a means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Firth, NE…

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 Firth, NE

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 12median — 10% chance by Sep 28
Growing season170 daysfrost-free, median

A hard freeze (28 °F) usually ends around April 13 and returns around October 22.

From the NOAA station Crete 4ese, NE — 15 miles away, elevation 1,460 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 68358

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 17 – Aug 31
GarlicPlant cloves · Sep 28 – Nov 2
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 23) and first fall frost (Oct 12) 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 68358 came on Mar 9 — 18 days earlier than the 1991–2020 average (Mar 27).

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 6a in Nebraska

432 plants native to the lower 48 states, recorded in Nebraska, and rated by the USDA to survive −10 °F or colder — the bottom of zone 6a. Each links to its USDA PLANTS profile.

Trees 31

American basswood100 ft · blooms late spring · low shade tolerance · to −46 °FAmerican elm120 ft · blooms early spring · medium shade tolerance · to −46 °FAmerican sycamore100 ft · blooms spring · medium shade tolerance · to −34 °Fbitternut hickory75 ft · blooms mid spring · high shade tolerance · to −47 °Fblack locust60 ft · blooms spring · high shade tolerance · to −37 °Fblack oak80 ft · blooms early spring · medium shade tolerance · to −30 °F

Shrubs 57

alderleaf mountain mahogany15 ft · blooms late spring · medium shade tolerance · to −41 °FAmerican black currant3 ft · blooms early spring · to −46 °FAmerican hazelnut10 ft · blooms spring · medium shade tolerance · to −33 °FAmerican plum24 ft · blooms mid spring · high shade tolerance · to −38 °Fantelope bitterbrush6 ft · blooms early spring · medium shade tolerance · to −36 °Fbig sagebrush4 ft · blooms mid summer · high shade tolerance · to −43 °F

Wildflowers & perennials 198

alkali buttercup1 ft · blooms late spring · low shade tolerance · to −38 °Falpine sweetvetch2 ft · blooms early summer · high shade tolerance · to −62 °FAmerican licorice4 ft · blooms late spring · medium shade tolerance · to −38 °FAmerican lotus3 ft · blooms mid summer · high shade tolerance · to −36 °FAmerican pokeweed7 ft · blooms mid summer · low shade tolerance · to −33 °FAmerican speedwell0.8 ft · blooms mid summer · low shade tolerance · to −38 °F

Grasses 130

alkali cordgrass3 ft · blooms late summer · high shade tolerance · to −38 °Falkali sacaton3 ft · blooms mid summer · high shade tolerance · to −38 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °Fbasin wildrye5 ft · blooms early spring · high shade tolerance · to −43 °Fbeaked spikerush3 ft · blooms late spring · high shade tolerance · to −28 °FBebb's sedge3 ft · blooms late spring · low shade tolerance · to −38 °F

Vines 8

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °Ffrost grape83 ft · blooms late spring · medium shade tolerance · to −23 °Friverbank grape45 ft · blooms late spring · medium shade tolerance · to −33 °Fsummer grape30 ft · blooms late spring · low shade tolerance · to −23 °Ftrumpet creeper2 ft · blooms summer · high shade tolerance · to −13 °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 Firth, NE.

Soil in Firth, NE

The soil mapped at the center of ZIP 68358 is Kennebec — silt loam, moderately well drained.

TextureSilt loama good balance for most vegetables
pH6.2slightly acidic; most vegetables like 6.0–7.0
DrainageModerately well drainednatural drainage class
Organic matter3%moderate
Hydrologic groupCwater soaks in slowly
Farmland classprime farmlandUSDA classification

Map unit: Kennebec silt loam, occasionally flooded.

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 68358; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Firth, NE

Summer high87 °Faverage high, July
Winter low14 °Faverage low, January
Hot days37days a year at 90 °F or more
Freezing nights133nights a year at 32 °F or less
Growing degree days3,441base 50 °F — the season’s usable heat
Longest day15 h 04 mindaylight on June 21
Shortest day9 h 16 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
Snowfall29 inper year

Average high and low, by month

0°10°20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 34 °F, low 14 °F 34°14° JanFebruary: average high 40 °F, low 18 °F 40°18° FebMarch: average high 52 °F, low 28 °F 52°28° MarApril: average high 63 °F, low 39 °F 63°39° AprMay: average high 73 °F, low 50 °F 73°50° MayJune: average high 83 °F, low 61 °F 83°61° JunJuly: average high 87 °F, low 65 °F 87°65° JulAugust: average high 85 °F, low 63 °F 85°63° AugSeptember: average high 78 °F, low 54 °F 78°54° SepOctober: average high 66 °F, low 41 °F 66°41° OctNovember: average high 51 °F, low 28 °F 51°28° NovDecember: average high 38 °F, low 18 °F 38°18° Dec

Precipitation by month inches · ❄ = snowfall

0″1″2″3″4″5″6″January: 0.73 in precipitation, 8 in snowfall 0.7❄8 JanFebruary: 0.97 in precipitation, 6.7 in snowfall 1.0❄7 FebMarch: 1.78 in precipitation, 5.1 in snowfall 1.8❄5 MarApril: 2.97 in precipitation, 1.6 in snowfall 3.0❄2 AprMay: 5.47 in precipitation 5.5 MayJune: 5.05 in precipitation 5.0 JunJuly: 3.54 in precipitation 3.5 JulAugust: 3.32 in precipitation 3.3 AugSeptember: 2.82 in precipitation 2.8 SepOctober: 2.48 in precipitation, 1.3 in snowfall 2.5❄1 OctNovember: 1.54 in precipitation, 1.8 in snowfall 1.5❄2 NovDecember: 1.03 in precipitation, 4.1 in snowfall 1.0❄4 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Crete 4ese, NE (15 mi away); precipitation: Hickman, NE (6 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 6a.

683726a
Hickman, NE · 5 mi
683016a
Adams, NE · 6 mi
683316a
Cortland, NE · 7 mi
684196a
Panama, NE · 7 mi
684386a
Sprague, NE · 10 mi
684046a
Martell, NE · 10 mi
684306a
Roca, NE · 10 mi
683686a
Hallam, NE · 11 mi

Nebraska planting zones →

Questions about 68358

What planting zone is ZIP code 68358?

ZIP code 68358 (Firth, NE) is in USDA hardiness zone 6a on the 2023 map: the coldest night of an average winter reaches −10 to −5 °F (−23.3 to −20.6 °C).

When is the last frost in Firth, NE?

The median last spring frost (32 °F) near 68358 is April 23; after May 6 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Crete 4ese station.

When is the first frost in Firth, NE?

The median first fall frost near 68358 is October 12, giving a median frost-free growing season of 170 days.

When should I plant tomatoes in 68358?

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 68358 get?

About 31.7 inches of precipitation a year and 29 inches of snowfall (NOAA 1991–2020 normals, Hickman station).

How hot do summers get in Firth, NE?

The average high peaks at 87 °F in July, with about 37 days a year at 90 °F or more.

What kind of soil does 68358 have?

The USDA soil survey maps Kennebec at the center of ZIP 68358: silt loam, moderately well drained, pH about 6.2 (slightly acidic).

Did spring come early in Firth, NE in 2026?

Spring leaf-out near 68358 came on Mar 9 in 2026, 18 days earlier than the 1991–2020 average (Mar 27), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Firth, NE?

Long-day onions: the longest day near 68358 is 15 h 04 min, so summer days reach 15+ hours, enough for long-day varieties (intermediate types work too).

Did the zone for 68358 change?

Yes. The 2012 USDA map put 68358 in zone 5b; the 2023 map puts it in zone 6a. The newer map uses 1991–2020 data and more weather stations.