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

Planting zone for 77580 — Mont Belvieu, TX

ZIP code 77580 (Mont Belvieu, Chambers County) is in USDA zone 9b: the coldest winter night averages 25 to 30 °F. The median last spring frost is February 20 and the first fall frost December 4.

Where ZIP 77580 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.

Zone9b25 to 30 °F
Coldest night−3.9 to −1.1 °C
Last frostFeb 20
First frostDec 4
2012 zone9a

Was 9a 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 9b means →

Frost forecast — next 7 nights

live from the National Weather Service

Loading the forecast for Mont Belvieu, TX…

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 Mont Belvieu, TX

JanFebMarAprMayJunJulAugSepOctNovDec
Blue: frost possible · fading green: frost risk falling or rising (90% → 10%) · green: frost-free
Last spring frostFebruary 20median — 50% chance of a later frost
Safe for tender plantsMarch 14only 10% chance of frost after
First fall frostDecember 4median — 10% chance by Nov 12
Growing season292 daysfrost-free, median

A hard freeze (28 °F) usually ends around January 30 and returns around December 28.

From the NOAA station Baytown, TX — 8 miles away, elevation 26 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 77580

JanFebMarAprMayJunJulAugSepOctNovDec
PeasSow outdoors · Jan 9 – Jan 23
SpinachSow outdoors · Jan 9 – Jan 30
Broccoli, cabbageStart indoors · Dec 12 – Dec 26
Broccoli, cabbageTransplant · Jan 30 – Feb 13
Onion setsPlant outdoors · Jan 23 – Feb 6
PotatoesPlant outdoors · Jan 30 – Feb 13
LettuceSow outdoors · Jan 23 – Feb 6
Carrots, beetsSow outdoors · Jan 30 – Feb 13
TomatoesStart indoors · Dec 26 – Jan 9
TomatoesTransplant · Feb 27 – Mar 13
Peppers, eggplantStart indoors · Dec 12 – Dec 26
Peppers, eggplantTransplant · Mar 6 – Mar 20
BeansSow outdoors · Feb 27 – Mar 13
Sweet cornSow outdoors · Feb 27 – Mar 13
Cucumbers, squashSow outdoors · Feb 27 – Mar 13
Fall lettuce, spinachSow outdoors · Oct 9 – Oct 23
GarlicPlant cloves · Nov 20 – Dec 25
Start seeds indoorsSow or plant outdoorsFall plantingMedian last & first frost

Counted from the median last spring frost (Feb 20) and first fall frost (Dec 4) 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 77580 came on Jan 15 — 8 days earlier than the 1991–2020 average (Jan 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).

Soil in Mont Belvieu, TX

The soil mapped at the center of ZIP 77580 is League — clay, somewhat poorly drained.

TextureClayholds water and nutrients; slow to drain and warm up
pH5.4strongly acidic; most vegetables like 6.0–7.0
DrainageSomewhat poorly drainedconsider raised beds
Organic matter2.1%moderate
Hydrologic groupDwater soaks in very slowly
Farmland classprime farmlandUSDA classification

Map unit: League clay, 0 to 1 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 77580; soils change within a few hundred feet, so a home soil test (pH, nutrients) is still the best guide.

Climate in Mont Belvieu, TX

Summer high92 °Faverage high, July
Winter low41 °Faverage low, January
Hot days84days a year at 90 °F or more
Freezing nights9nights a year at 32 °F or less
Growing degree days7,082base 50 °F — the season’s usable heat
Longest day14 h 04 mindaylight on June 21
Shortest day10 h 13 mindaylight on December 21
Onions to growShort-daysummer days stay under about 14 h 20 min, so long-day varieties won’t bulb
Precipitation64.7 inper year, rain and melted snow

Average high and low, by month

30°40°50°60°70°80°90°100°32 °FJanuary: average high 63 °F, low 41 °F 63°41° JanFebruary: average high 66 °F, low 45 °F 66°45° FebMarch: average high 72 °F, low 52 °F 72°52° MarApril: average high 78 °F, low 59 °F 78°59° AprMay: average high 84 °F, low 67 °F 84°67° MayJune: average high 89 °F, low 73 °F 89°73° JunJuly: average high 92 °F, low 75 °F 92°75° JulAugust: average high 92 °F, low 74 °F 92°74° AugSeptember: average high 89 °F, low 69 °F 89°69° SepOctober: average high 82 °F, low 60 °F 82°60° OctNovember: average high 71 °F, low 50 °F 71°50° NovDecember: average high 65 °F, low 44 °F 65°44° Dec

Precipitation by month inches

0″2″4″6″8″January: 4.85 in precipitation 4.8 JanFebruary: 3.78 in precipitation 3.8 FebMarch: 3.94 in precipitation 3.9 MarApril: 4.51 in precipitation 4.5 AprMay: 6.01 in precipitation 6.0 MayJune: 7.08 in precipitation 7.1 JunJuly: 5.49 in precipitation 5.5 JulAugust: 6.82 in precipitation 6.8 AugSeptember: 6.41 in precipitation 6.4 SepOctober: 6.13 in precipitation 6.1 OctNovember: 4.94 in precipitation 4.9 NovDecember: 4.77 in precipitation 4.8 Dec

NOAA NCEI U.S. Climate Normals 1991–2020 — temperature: Baytown, TX (8 mi away); precipitation: Baytown, TX (8 mi away). Daylight is calculated from latitude.

Nearby ZIP codes

All 8 nearest ZIP codes share zone 9b.

775219b
Baytown, TX · 6 mi
775239b
Baytown, TX · 6 mi
775229b
Baytown, TX · 10 mi
775629b
Highlands, TX · 11 mi
775979b
Wallisville, TX · 11 mi
775209b
Baytown, TX · 11 mi
775329b
Crosby, TX · 12 mi
775359b
Dayton, TX · 14 mi

Texas planting zones →

Questions about 77580

What planting zone is ZIP code 77580?

ZIP code 77580 (Mont Belvieu, TX) is in USDA hardiness zone 9b on the 2023 map: the coldest night of an average winter reaches 25 to 30 °F (−3.9 to −1.1 °C).

When is the last frost in Mont Belvieu, TX?

The median last spring frost (32 °F) near 77580 is February 20; after March 14 there is only a 10% chance of frost. Data: NOAA 1991–2020 normals, Baytown station.

When is the first frost in Mont Belvieu, TX?

The median first fall frost near 77580 is December 4, giving a median frost-free growing season of 292 days.

When should I plant tomatoes in 77580?

Start tomato seeds indoors around Dec 26 – Jan 9 and set transplants outside around Feb 27 – Mar 13, one to three weeks after the median last frost.

How much rain and snow does 77580 get?

About 64.7 inches of precipitation a year (NOAA 1991–2020 normals, Baytown station).

How hot do summers get in Mont Belvieu, TX?

The average high peaks at 92 °F in July, with about 84 days a year at 90 °F or more.

What kind of soil does 77580 have?

The USDA soil survey maps League at the center of ZIP 77580: clay, somewhat poorly drained, pH about 5.4 (strongly acidic).

Did spring come early in Mont Belvieu, TX in 2026?

Spring leaf-out near 77580 came on Jan 15 in 2026, 8 days earlier than the 1991–2020 average (Jan 23), according to the USA National Phenology Network Spring Index.

What kind of onions grow in Mont Belvieu, TX?

Short-day onions: the longest day near 77580 is 14 h 04 min, so summer days stay under about 14 h 20 min, so long-day varieties won’t bulb.

Did the zone for 77580 change?

Yes. The 2012 USDA map put 77580 in zone 9a; the 2023 map puts it in zone 9b. The newer map uses 1991–2020 data and more weather stations.