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When to plant in Roma, TX

USDA Zone 9b

Here are the average frost dates, USDA hardiness zone, and a month-by-month planting calendar for Roma, Texas — all computed from Roma's nearest NOAA weather station.

With about 320 frost-free days, Roma supports back-to-back plantings; stagger sowings every few weeks to keep beds productive spring through fall. Roma's nearest full-normals station sits about 20 km out, so treat these as a close estimate — local microclimate can nudge your first and last frost. Zone 9b is warm enough that Roma can grow subtropical perennials, and the short (or absent) frost period barely limits the annual calendar.

Station · RIO GRANDE CITY · 19.6 km
Last spring frost
January 31
50% chance · 32°F
First fall frost
December 17
50% chance · 32°F
Growing season
320 days
frost-free
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Frost calendar for RomaA year-band showing 32°F frost risk from January to December for Roma: last spring frost around January 31, first fall frost around December 17, about 320 frost-free days between.
Shaded months carry frost risk; the clear span is the average frost-free season.

Frost probability

RIO GRANDE CITY · 1991–2020

The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are Roma’s own odds, recorded at RIO GRANDE CITY.

Frost-probability curves for RomaProbability of the last spring frost and first fall frost by date at 32°F. The last spring frost is most likely around January 31 and the first fall frost around December 17, giving about 320 frost-free days.
Last spring frostFirst fall frostbold = 32°F · thin = 28°F / 36°F · dot = 50% date · band = 10–90% window
ThresholdSPRING 10%SPRING 50%SPRING 90%FALL 10%FALL 50%FALL 90%
36°FMar 14Feb 22Jan 22Nov 11Dec 1Dec 28
32°FMar 4Jan 31Dec 29Nov 22Dec 17Jan 20
28°FFeb 20Jan 12Dec 13Dec 2Dec 29Feb 1

Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.

What to plant now

TODAY · JULY 19

Nothing new to sow or transplant outdoors in the next few weeks — a seasonal lull. Check the full-year calendar below for the next window.

Add the next planting windows to your calendar (.ics) ↓

Full-year planting calendar

Start indoorsTransplantDirect sowFall sow

Each bar is the exact window to take a planting action in Roma, drawn to the day from the local frost dates. The dashed line is today.

Nearby weather stations

2 within 21 km · complete 32°F normals

When stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.

RIO GRANDE CITY
Primary
20 km · 52 m elevation
SPRING
Jan 31
FALL
Dec 17
FALCON DAM
21 km · 98 m elevation
SPRING
Jan 9
FALL
Jan 1

Roma planting FAQ

When is the last spring frost in Roma, TX?

Plan for the last spring frost in Roma around January 31 (the date it has a 50% chance of a 32°F freeze). Anything frost-sensitive should go out after it.

When is the first fall frost in Roma, TX?

In Roma, the first 32°F freeze of fall lands around December 17 on average. Time your last harvests and any season-extension cover before it.

What hardiness zone is Roma in?

Roma is in USDA hardiness zone 9b. In zone 9b, winters are mild — many tender perennials overwinter here.

How long is the growing season in Roma?

There are roughly 320 frost-free days in Roma (a long growing season), running from the average last frost around January 31 to the first fall frost near December 17.

When should I plant tomatoes in Roma?

In Roma, start tomato seeds indoors around December 6–December 20, then transplant seedlings outdoors around February 7 once the danger of frost has passed.

Planting reminders

Never miss a window in Roma

An email when it’s time to start seeds, transplant, and sow — timed to Roma’s frost dates. Double opt-in, one-click unsubscribe, no spam.

Nearby cities

8 within reach

Frost dates recorded at RIO GRANDE CITY, 20 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.

Cite this page
BlissGarden. "When to Plant in Roma, TX — Frost Dates & Zone 9b." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00417622. Retrieved from https://blissgarden.com/texas/roma.