Rio Grande City, Texas, sits in USDA hardiness zone 9b — enough range to grow cool-season vegetables, hardy fruit, and warm-season crops that mature before the first hard frost.
A short list that earns its place here — okra, meyer lemon, california poppy, and artichoke — with any one site's soil, sun, and drainage making the final cut.
Even in Rio Grande City, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single Rio Grande City lot. Enter your address and we'll score 1,086 plants against your land's actual soil, sun, and frost.
We read public map data around Rio Grande City — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Rio Grande City — the short answer
Rio Grande City, Texas: USDA zone 9b, about 322 days between hard freezes, across 7K acres of city.
- USDA zone
- 9b
- USDA PHZM 2023
- Last hard freeze (28°F)
- Jan 21
- Starr County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Dec 9
- Starr County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~322
- Starr County normal — NOAA 1991–2020, nearest to this town
- City area
- 7K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. No 30-year normal resolves at this town’s own centroid, so the hard-freeze dates are Starr County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 9b is Rio Grande City's average, not your lot's — a low corner or a tree line moves it. Against Rio Grande City's 322-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Rio Grande City
Each reading below is measured for Rio Grande City itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsRio Grande City runs about 322 days between hard freezes (read from Starr County, the closest normal to Rio Grande City) — close to year-round growing.
Frost is rarely the limit here; winter plantings are as real as summer ones, and the harder question is which crops shrug off the summer heat.
Grow cool-season crops through the mild winter, and choose heat-tolerant varieties for the summer beds.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredRio Grande City sits in USDA hardiness zone 9b.
The zone sets which perennials, shrubs, and fruit trees live through an average winter here — a plant rated for a colder zone is a safe bet, one rated warmer needs winter protection or gets treated as an annual.
Match perennials and fruit to the zone before you buy, so nothing you plant is a gamble against the cold.
USDA PHZM 2023
The kind of country Rio Grande City is in
Rio Grande City sits in the Southern Texas Plains — EPA Level III, inside the wider Great Plains. That is read at Rio Grande City's own centroid rather than borrowed from Starr County.
What Grows in Rio Grande City
Every plant below cleared Rio Grande City's own zone 9b and its 322-day season. Each card opens that plant's Texas profile. How we score.
Is it too late to plant in Rio Grande City?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Jan 1; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Jan 21 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Dec 9 — long-season crops need about 90 days of runway, quick greens only 30. In a climate this gentle, “too late” hardly applies — the question becomes which crops prefer the cooler months ahead.
What's on the federal record near Rio Grande City
Closest first, within ~10 miles of Rio Grande City. Listing isn't leaking, and distance isn't exposure.
- ZAMORAS EXXONUnderground Storage Tanks · 500 ft
- LEOS SMALL ENGINE REPAIRUnderground Storage Tanks · 850 ft
- RIO GRANDE CITY CENTRAL OFFICEUnderground Storage Tanks · 900 ft
- 3M NATIONAL ADVTSNGBrownfields · 900 ft
- RUNNERS CONVENIENCE STOREUnderground Storage Tanks · 1000 ft
- RAMIREZ FORD SALESUnderground Storage Tanks · 1300 ft
- GUERRA SERV STAUnderground Storage Tanks · 1300 ft
- RAMIREZ FIRESTONE-CONOCOUnderground Storage Tanks · 1400 ft
- WEST END TEXACOUnderground Storage Tanks · 1400 ft
- FORMER SUPER CIRCLE 7 FOOD STOREUnderground Storage Tanks · 1500 ft
- THE COUNTRY STORE 3Underground Storage Tanks · 2100 ft
- L F GARZA EXXON SERVICE STATIONUnderground Storage Tanks · 2300 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Rio Grande City's center, not your beds. Run your own address for what's upwind of you specifically.
Environmental Intelligence
The counts behind that headline — every source type on the record near Rio Grande City.
Total Sites
68
within ~10 miles of Rio Grande City
Risk Level
Moderate
Highest-severity
1 concentrated animal feeding operation
Sources Checked
within ~10 miles of Rio Grande City
Severity Distribution
within ~10 miles of Rio Grande City
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Rio Grande City, Underground Storage Tanks runs higher than the national average — 60 sites within ~10 miles of Rio Grande City. Knowing it is half the work — and it's nothing a thoughtful grower can't plan for.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Rio Grande City
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,086 plant recommendations.
25+ data sources read at your address, not the Rio Grande City average
Your land is one point inside Rio Grande City
Everything above resolves to Rio Grande City as a whole — one PHZM band, read across 7K acres, with hard-freeze dates borrowed from Starr County’s record because no 30-year normal resolves at this city’s own centroid. Your parcel is one point inside that footprint. Slope, tree cover, a low spot that pools cold air, and what is in the soil are all resolved at the address, and none of them are visible at city scale. That is the honest boundary of this page, and the reason the next step is a reading of your own ground rather than a better local average.
Your Lot vs the Rio Grande City Average
Rio Grande City Average
- ●USDA Zones 9b, averaged across Rio Grande City
- ●One soil character for all of Rio Grande City
- ●Frost dates read at Rio Grande City's scale: Jan 21 to Dec 9
YOUR Parcel
- ✓Your exact zone, not Rio Grande City's 9b
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Rio Grande City
Pull a site-specific report for your exact address in Rio Grande City, Texas — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Rio Grande City averages can't show:
We read public map data around Rio Grande City — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Rio Grande City average
How we know this about Rio Grande City
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Starr County’s record, because none resolves here; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at city grain anywhere on this page — there is no city-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about Rio Grande City
When does frost risk typically end in Rio Grande City?
The last hard freeze (28°F) in Rio Grande City typically lands around Jan 21, per NOAA 1991–2020 climate normals — earlier than the light-frost dates most charts quote. That marks the hard freeze, not the last light frost — lighter frosts keep biting past it, which is why tender transplants here wait until about Feb 11.
When is the first frost in Rio Grande City?
The first hard freeze (28°F) in Rio Grande City typically arrives around Dec 9, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Nov 25, so the watching starts about Nov 9 — about 322 days after the spring freeze cleared.
How long is the growing season in Rio Grande City?
Measured between 28°F hard freezes, Rio Grande City sees about 322 frost-free days — roughly Jan 21 through Dec 9, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Feb 11 to Nov 25, about 287 days.
Is the soil safe to grow vegetables in Rio Grande City?
The federal record around Rio Grande City shows 68 documented sites, mostly Underground Storage Tanks entries (60), the nearest Underground Storage Tanks record under a tenth of a mile out — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
How do I protect my plants from frost in Rio Grande City?
From about Nov 9 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Dec 9 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Dec 9. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Rio Grande City's scale — its 9b band and its 322-day season. Your yard writes its own version of Rio Grande City's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at Rio Grande City’s own scale
5 of the readings below were taken at Rio Grande City's own scale — the 7,265 acres it covers and 68 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Rio Grande City's own USDA hardiness band, zones 9bUSDA PHZM 2023
- 68 documented contamination sites on the federal record near Rio Grande City, the closest Underground Storage Tanks record under a tenth of a mile out from the town centreFederal environmental registers
- Rio Grande City's boundary and the 7,265 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 9b and a ~322-day seasonGrowable Ground crop-matching engine
- The ecoregion at Rio Grande City's own centroid, the Southern Texas PlainsUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Rio Grande City has no normal of its own, so its county's is the closest measured readfrom Starr County
- Soil character — no town-scale survey exists, so Rio Grande City's 7,265 acres read through its county's SSURGO summaryfrom Starr County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Starr County
- The growing challenges every Texas grower plans around — written at state scale, so they stay on the state guidefrom Texas
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Starr County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Rio Grande City's 7,265 acreswhy one lot differs from the next →
- Which side of Rio Grande City you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 7,265 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record under a tenth of a mile out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any Rio Grande City-wide figureread your own land →