USDA Hardiness Zone 9a
Frost Dates for 77471 — Rosenberg, Texas
NOAA 1991–2020 normals from Sugar Land, TX (84 ft), 11 miles northeast.
Updated
In Rosenberg, the last spring frost (32°F) is around February 9 in half of years and has passed by March 11 in nine years out of ten. The first fall frost comes around December 13, as early as November 19 one year in ten, leaving a typical freeze-free season of 305 days (NOAA, Sugar Land, TX).
- Last spring frost
- February 9
- First fall frost
- December 13
- Growing season
- 305 days
- Hardiness zone
- 9a
50% probability
50% probability
freeze-free, 50%
20 to 25°F (-6.7 to -3.9°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 19 observed
NOAA normal
Frost risk by date in Rosenberg
Half of springs at Sugar Land, TX see their last 32°F night by February 9; only one in ten is past it by January 13, and one in ten still has one after March 11. Planting tender crops after February 26 leaves a 30% risk of a frost on them, after March 3 20%, and after March 11 10%. The 30 days between the even-odds date and the one-in-ten date is wider than at 91% 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 December 13 in half of years, as early as November 19 one year in ten, and holds off past January 13 one year in ten. A hard freeze of 28°F follows 19 days later, around January 1; in spring the one-in-ten date for 28°F is February 28, 11 days before the 32°F one. The freeze-free season lasts 305 days in a typical year, longer than at 90% of the 339 Texas stations; it reaches 340 days one year in ten and falls short of 269 one year in ten. On average 7 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 March 2, and return around November 29. A 24°F night is unusual: 39% of winters had one.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Feb 2 | Feb 12 | Feb 19 | Feb 26 | Mar 2 | Mar 6 | Mar 10 | Mar 15 | Mar 25 |
| 32°F98% of yrs | Jan 13 | Jan 23 | Jan 30 | Feb 3 | Feb 9 | Feb 17 | Feb 26 | Mar 3 | Mar 11 |
| 28°F78% of yrs | Dec 26 | Jan 7 | Jan 16 | Jan 21 | Jan 28 | Feb 2 | Feb 8 | Feb 18 | Feb 28 |
| 24°F39% of yrs | too rare for a date | ||||||||
| 20°F14% of yrs | too rare for a date | ||||||||
| 16°F3% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Nov 9 | Nov 16 | Nov 21 | Nov 26 | Nov 29 | Dec 2 | Dec 6 | Dec 12 | Dec 20 |
| 32°F98% of yrs | Nov 19 | Nov 27 | Dec 2 | Dec 7 | Dec 13 | Dec 20 | Dec 28 | Jan 3 | Jan 13 |
| 28°F78% of yrs | Nov 30 | Dec 9 | Dec 18 | Dec 27 | Jan 1 | Jan 5 | Jan 10 | Jan 19 | Feb 2 |
| 24°F39% of yrs | too rare for a date | ||||||||
| 20°F14% of yrs | too rare for a date | ||||||||
| 16°F3% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Sugar Land, 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 77471 →Compare Rosenberg with another place →
Weather by month in Rosenberg
August is the warmest month at Sugar Land, TX, averaging 94°F by day and 76°F at night; January is the coldest at 64°F and 43°F. From April to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 55% of years and March still brings one in 24% of years.
Warmth for growing adds up to 7,712 growing degree days a year (base 50°F), more than at 83% of the 351 Texas stations. 43% of them (3,315) have built up by the end of June, and August adds the most, 1,091. Precipitation totals 51.1 inches a year, most in June (5.7") and least in February (3.0"); May to September bring 47% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 64 | 43 | 3.9 | 77% | 3 | 175 |
| Feb | 68 | 48 | 3.0 | 55% | 1 | 253 |
| Mar | 74 | 54 | 3.6 | 24% | <1 | 442 |
| Apr | 81 | 60 | 3.6 | 0% | 0 | 608 |
| May | 87 | 68 | 4.3 | 0% | 0 | 851 |
| Jun | 92 | 74 | 5.7 | 0% | 0 | 987 |
| Jul | 94 | 76 | 3.8 | 0% | 0 | 1088 |
| Aug | 94 | 76 | 5.0 | 0% | 0 | 1091 |
| Sep | 90 | 71 | 5.3 | 0% | 0 | 915 |
| Oct | 83 | 62 | 5.2 | 0% | <1 | 700 |
| Nov | 73 | 53 | 4.4 | 26% | 1 | 388 |
| Dec | 66 | 45 | 3.3 | 63% | 2 | 214 |
Monthly normals 1991–2020 at Sugar Land, TX (84 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, Houston Sugarland Mem, TX, 11 miles northeast of Rosenberg, has a last frost 7 days earlier (February 2), a first frost 2 days earlier (December 11), a season 13 days longer.
When it snows in Rosenberg, Texas
Measurable snow is rare here: only 0 of 19 winters from 1991 to 2020 recorded 0.1 inch or more at Richmond, TX, 4.5 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 77471
| When | What to do |
|---|---|
| December 1 – December 15 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| December 15 – December 29 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| January 12 – January 26 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| February 9 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by September 20 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by November 29 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| December 13 onward | Plant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter. |
The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.
Where these figures come from
ZIP 77471 is 11 miles from Sugar Land, TX, which stands at 84 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 77479 (Sugar Land). The 2023 USDA Plant Hardiness Zone Map lists ZIP 77471 in zone 9a, the band where the coldest night of the year averaged 20 to 25°F (-6.7 to -3.9°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.