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

Planting zone for 28628 — Glen Alpine, NC

ZIP code 28628 (Glen Alpine, Burke County) is in USDA zone 7b: the coldest winter night averages 5 to 10 °F. The median last spring frost is April 7 and the first fall frost October 28.

Where ZIP 28628 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.

Zone7b5 to 10 °F
Coldest night−15 to −12.2 °C
Last frostApr 7
First frostOct 28
2012 zone7b

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 7b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Glen Alpine, NC…

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 Glen Alpine, NC

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostApril 7median — 50% chance of a later frost
Safe for tender plantsApril 26only 10% chance of frost after
First fall frostOctober 28median — 10% chance by Oct 14
Growing season202 daysfrost-free, median

A hard freeze (28 °F) usually ends around March 28 and returns around November 6.

From the NOAA station Morganton, NC — 6 miles away, elevation 1,181 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 28628

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Feb 24 – Mar 10
SpinachSow outdoors · Feb 24 – Mar 17
Broccoli, cabbageStart indoors · Jan 27 – Feb 10
Broccoli, cabbageTransplant · Mar 17 – Mar 31
Onion setsPlant outdoors · Mar 10 – Mar 24
PotatoesPlant outdoors · Mar 17 – Mar 31
LettuceSow outdoors · Mar 10 – Mar 24
Carrots, beetsSow outdoors · Mar 17 – Mar 31
TomatoesStart indoors · Feb 10 – Feb 24
TomatoesTransplant · Apr 14 – Apr 28
Peppers, eggplantStart indoors · Jan 27 – Feb 10
Peppers, eggplantTransplant · Apr 21 – May 5
BeansSow outdoors · Apr 14 – Apr 28
Sweet cornSow outdoors · Apr 14 – Apr 28
Cucumbers, squashSow outdoors · Apr 14 – Apr 28
Fall lettuce, spinachSow outdoors · Sep 2 – Sep 16
GarlicPlant cloves · Oct 14 – Nov 18
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Apr 7) and first fall frost (Oct 28) 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 28628 came on Feb 22 — about the same time as the 1991–2020 average (Feb 23).

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 7b in North Carolina

596 plants native to the lower 48 states, recorded in North Carolina, and rated by the USDA to survive 5 °F or colder — the bottom of zone 7b. Each links to its USDA PLANTS profile.

Trees 89

American basswood100 ft · blooms late spring · low shade tolerance · to −46 °FAmerican beech80 ft · blooms mid spring · low shade tolerance · to −44 °FAmerican chestnut115 ft · blooms early summer · high shade tolerance · to −33 °FAmerican elm120 ft · blooms early spring · medium shade tolerance · to −46 °FAmerican sycamore100 ft · blooms spring · medium shade tolerance · to −34 °Farborvitae50 ft · blooms mid spring · medium shade tolerance · to −33 °F

Shrubs 129

Allegheny serviceberry35 ft · blooms early spring · low shade tolerance · to −38 °Faloe yucca15 ft · blooms early summer · medium shade tolerance · to −1 °Falternateleaf dogwood25 ft · blooms mid spring · low shade tolerance · to −47 °FAmerican beautyberry6 ft · blooms early summer · medium shade tolerance · to −8 °FAmerican hazelnut10 ft · blooms spring · medium shade tolerance · to −33 °FAmerican holly40 ft · blooms mid spring · low shade tolerance · to −20 °F

Wildflowers & perennials 186

American bur-reed3 ft · blooms indeterminate · medium shade tolerance · to −33 °FAmerican eelgrass1 ft · blooms mid summer · high shade tolerance · to −33 °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 °FAmerican spongeplant0.5 ft · blooms mid spring · high shade tolerance · to −24 °F

Grasses 165

American beachgrass2.5 ft · blooms spring · high shade tolerance · to −28 °FAmerican cupscale3 ft · blooms early summer · high shade tolerance · to −18 °FAtlantic mannagrass3 ft · blooms summer · low shade tolerance · to −8 °Fautumn bluegrass1.5 ft · blooms late spring · medium shade tolerance · to −8 °Fawlfruit sedge4 ft · blooms mid spring · low shade tolerance · to −38 °FBailey's sedge2.1 ft · blooms late spring · low shade tolerance · to −33 °F

Vines 12

American bittersweet15 ft · blooms spring · low shade tolerance · to −38 °FAmerican wisteria50 ft · blooms spring · low shade tolerance · to −3 °Fdevil's darning needles15 ft · blooms mid summer · medium shade tolerance · to −38 °Ffrost grape83 ft · blooms late spring · medium shade tolerance · to −23 °Fgraybark grape50 ft · blooms late spring · medium shade tolerance · to −8 °Fheartleaf peppervine2 ft · blooms late spring · low shade tolerance · to −8 °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 Glen Alpine, NC.

Soil in Glen Alpine, NC

The soil mapped at the center of ZIP 28628 is Fairview — sandy clay loam, well drained.

TextureSandy clay loamholds water and nutrients; slow to drain and warm up
pH5.7moderately acidic; most vegetables like 6.0–7.0
DrainageWell drainednatural drainage class
Organic matter1%low — add compost
Hydrologic groupBwater soaks in moderately
Farmland classprime farmlandUSDA classification

Map unit: Fairview sandy clay loam, 2 to 8 percent slopes, moderately eroded.

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 28628; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Glen Alpine, NC

Summer high88 °Faverage high, July
Winter low28 °Faverage low, January
Hot days35days a year at 90 °F or more
Freezing nights91nights a year at 32 °F or less
Growing degree days4,141base 50 °F — the season’s usable heat
Longest day14 h 35 mindaylight on June 21
Shortest day9 h 44 mindaylight on December 21
Onions to growIntermediateday-neutral types bulb best; long-day varieties may not bulb fully
Precipitation52.8 inper year, rain and melted snow

Average high and low, by month

20°30°40°50°60°70°80°90°100°32 °FJanuary: average high 49 °F, low 28 °F 49°28° JanFebruary: average high 53 °F, low 30 °F 53°30° FebMarch: average high 61 °F, low 37 °F 61°37° MarApril: average high 71 °F, low 45 °F 71°45° AprMay: average high 78 °F, low 54 °F 78°54° MayJune: average high 85 °F, low 62 °F 85°62° JunJuly: average high 88 °F, low 66 °F 88°66° JulAugust: average high 86 °F, low 65 °F 86°65° AugSeptember: average high 80 °F, low 59 °F 80°59° SepOctober: average high 71 °F, low 46 °F 71°46° OctNovember: average high 61 °F, low 35 °F 61°35° NovDecember: average high 52 °F, low 30 °F 52°30° Dec

Precipitation by month inches

0″1″2″3″4″5″6″January: 4.07 in precipitation 4.1 JanFebruary: 3.72 in precipitation 3.7 FebMarch: 4.35 in precipitation 4.3 MarApril: 4.29 in precipitation 4.3 AprMay: 4.53 in precipitation 4.5 MayJune: 4.88 in precipitation 4.9 JunJuly: 4.72 in precipitation 4.7 JulAugust: 4.85 in precipitation 4.8 AugSeptember: 5.42 in precipitation 5.4 SepOctober: 3.58 in precipitation 3.6 OctNovember: 3.89 in precipitation 3.9 NovDecember: 4.50 in precipitation 4.5 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Morganton, NC (6 mi away); precipitation: Glen Alpine 0.7 Wsw, NC (within 1 mile). Daylight is calculated from latitude.

Nearby ZIP codes

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

286557b
Morganton, NC · 3 mi
286807b
Morganton, NC · 5 mi
287617b
Nebo, NC · 8 mi
286197b
Drexel, NC · 10 mi
286907b
Valdese, NC · 11 mi
286718a
Rutherford College, NC · 14 mi
287527b
Marion, NC · 14 mi
286128a
Connelly Springs, NC · 15 mi

North Carolina planting zones →

Questions about 28628

What planting zone is ZIP code 28628?

ZIP code 28628 (Glen Alpine, NC) is in USDA hardiness zone 7b on the 2023 map: the coldest night of an average winter reaches 5 to 10 °F (−15 to −12.2 °C).

When is the last frost in Glen Alpine, NC?

The median last spring frost (32 °F) near 28628 is April 7; after April 26 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Morganton station.

When is the first frost in Glen Alpine, NC?

The median first fall frost near 28628 is October 28, giving a median frost-free growing season of 202 days.

When should I plant tomatoes in 28628?

Start tomato seeds indoors around Feb 10 – Feb 24 and set transplants outside around Apr 14 – Apr 28, one to three weeks after the median last frost.

How much rain and snow does 28628 get?

About 52.8 inches of precipitation a year (NOAA 1991–2020 normals, Glen Alpine 0.7 Wsw station).

How hot do summers get in Glen Alpine, NC?

The average high peaks at 88 °F in July, with about 35 days a year at 90 °F or more.

What kind of soil does 28628 have?

The USDA soil survey maps Fairview at the center of ZIP 28628: sandy clay loam, well drained, pH about 5.7 (moderately acidic).

Did spring come early in Glen Alpine, NC in 2026?

Spring leaf-out near 28628 came on Feb 22 in 2026, about the same as the 1991–2020 average (Feb 23), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Glen Alpine, NC?

Intermediate onions: the longest day near 28628 is 14 h 35 min, so day-neutral types bulb best; long-day varieties may not bulb fully.