USDA Hardiness Zone 9b
Frost Dates for 78584 — Roma, Texas
NOAA 1991–2020 normals from Falcon Dam, TX (320 ft), 9 miles northwest.
Updated
A freeze (32°F) reaches Roma in 55% of winters. When it does, the first freeze of winter comes around January 1 and the last freeze of winter around January 9; after February 21 the chance of another is under 5%.
- Last freeze
- January 9
- First freeze
- January 1
- Winters with a freeze
- 55%
- Hardiness zone
- 9b
50%, in freezing years
50%, in freezing years
32°F or below, 1991–2020
25 to 30°F (-3.9 to -1.1°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 0%
- Snow per year
- 0"
median, 1991–2020
median, 1991–2020
0 of 20 observed
NOAA normal
Frost risk by date in Roma
In the 55% of winters that bring a 32°F night, half of winters at Falcon Dam, TX see their last 32°F night by January 9; only one in ten is past it by December 17, and one in ten still has one after February 21. Counting the winters with no freeze at all, the risk of a 32°F night after February 21 is under 5% and after January 9 27%. The 43 days between the even-odds date and the one-in-ten date is wider than at 100% of the 339 Texas stations behind this site's ZIP pages, so a fixed calendar date is a gamble here.
In fall the first 32°F night comes by January 1 in half of years, as early as December 8 one year in ten, and holds off past February 4 one year in ten. A hard freeze of 28°F is less common: it came in 19% of winters. On average 2 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 21 days longer, to about January 30, and return around December 18. A 24°F night is unusual: 4% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F92% of yrs | Dec 27 | Jan 6 | Jan 16 | Jan 23 | Jan 30 | Feb 6 | Feb 16 | Feb 25 | Mar 5 |
| 32°F55% of yrs | Dec 17 | Dec 27 | Jan 1 | Jan 5 | Jan 9 | Jan 16 | Jan 24 | Feb 3 | Feb 21 |
| 28°F19% of yrs | too rare for a date | ||||||||
| 24°F4% of yrs | too rare for a date | ||||||||
| 20°F0% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F92% of yrs | Nov 27 | Dec 3 | Dec 7 | Dec 11 | Dec 18 | Dec 24 | Dec 30 | Jan 5 | Jan 14 |
| 32°F55% of yrs | Dec 8 | Dec 18 | Dec 25 | Dec 29 | Jan 1 | Jan 5 | Jan 9 | Jan 20 | Feb 4 |
| 28°F19% of yrs | too rare for a date | ||||||||
| 24°F4% of yrs | too rare for a date | ||||||||
| 20°F0% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Falcon Dam, TX, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.
Frost risk on any date in 78584 →Compare Roma with another place →
Weather by month in Roma
August is the warmest month at Falcon Dam, TX, averaging 103°F by day and 77°F at night; January is the coldest at 72°F and 49°F. From March to November the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 11% of years.
Warmth for growing adds up to 9,758 growing degree days a year (base 50°F), more than at 100% of the 351 Texas stations. 46% of them (4,469) have built up by the end of June, and August adds the most, 1,229. Precipitation totals 19.4 inches a year, most in September (4.9") and least in February (0.6"); May to September bring 64% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 72 | 49 | 0.7 | 30% | 1 | 333 |
| Feb | 77 | 53 | 0.6 | 11% | 1 | 424 |
| Mar | 84 | 59 | 0.8 | 2% | <1 | 668 |
| Apr | 91 | 65 | 1.2 | 0% | 0 | 834 |
| May | 97 | 72 | 2.0 | 0% | 0 | 1056 |
| Jun | 101 | 76 | 1.9 | 0% | 0 | 1155 |
| Jul | 102 | 77 | 2.0 | 0% | 0 | 1221 |
| Aug | 103 | 77 | 1.6 | 0% | 0 | 1229 |
| Sep | 96 | 73 | 4.9 | 0% | 0 | 1038 |
| Oct | 90 | 66 | 1.4 | 0% | 0 | 867 |
| Nov | 80 | 58 | 1.3 | 1% | 0 | 572 |
| Dec | 72 | 50 | 1.0 | 24% | 1 | 361 |
Monthly normals 1991–2020 at Falcon Dam, TX (320 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.
Compared with the next station
The nearest other station, Rio Grande City, TX, 15 miles southeast of Roma, has a last frost 22 days later (January 31), a first frost 15 days earlier (December 17), a season 42 days shorter.
When it snows in Roma, Texas
Measurable snow is rare here: only 0 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Falcon Dam, TX, 9.2 miles away, so there is no typical first-snow date to plan around.
Where these figures come from
ZIP 78584 is 9 miles from Falcon Dam, TX, which stands at 320 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 78584 in zone 9b, the band where the coldest night of the year averaged 25 to 30°F (-3.9 to -1.1°C) over 1991–2020; a zone describes winter lows, not frost dates.
Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.
Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.