USDA Hardiness Zone 8b
Frost Dates for 78070 — Spring Branch, Texas
NOAA 1991–2020 normals from Canyon Dam, TX (1,000 ft), 13 miles east.
Updated
In Spring Branch, the last spring frost (32°F) is around March 1 in half of years and has passed by March 22 in nine years out of ten. The first fall frost comes around December 1, as early as November 9 one year in ten, leaving a typical freeze-free season of 276 days (NOAA, Canyon Dam, TX).
- Last spring frost
- March 1
- First fall frost
- December 1
- Growing season
- 276 days
- Hardiness zone
- 8b
50% probability
50% probability
freeze-free, 50%
15 to 20°F (-9.4 to -6.7°C) coldest night
- First snow
- Rare
- Last snow
- Rare
- Winters with snow
- 5%
- Snow per year
- 0.1"
median, 1991–2020
median, 1991–2020
1 of 20 observed
NOAA normal
Frost risk by date in Spring Branch
Half of springs at Canyon Dam, TX see their last 32°F night by March 1; only one in ten is past it by January 31, and one in ten still has one after March 22. Planting tender crops after March 8 leaves a 30% risk of a frost on them, after March 13 20%, and after March 22 10%. The 21 days between the even-odds date and the one-in-ten date is wider than at 50% 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 1 in half of years, as early as November 9 one year in ten, and holds off past December 26 one year in ten. A hard freeze of 28°F follows 18 days later, around December 19; in spring the one-in-ten date for 28°F is March 9, 13 days before the 32°F one. The freeze-free season lasts 276 days in a typical year, longer than at 76% of the 339 Texas stations; it reaches 313 days one year in ten and falls short of 244 one year in ten. On average 18 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 11 days longer, to about March 12, and return around November 16. Nights of 24°F, cold enough to damage hardier plants, come in 65% of winters and 16°F in 4%.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Feb 21 | Feb 28 | Mar 4 | Mar 8 | Mar 12 | Mar 17 | Mar 21 | Mar 28 | Apr 4 |
| 32°F | Jan 31 | Feb 13 | Feb 20 | Feb 25 | Mar 1 | Mar 4 | Mar 8 | Mar 13 | Mar 22 |
| 28°F96% of yrs | Jan 4 | Jan 18 | Jan 27 | Feb 1 | Feb 10 | Feb 16 | Feb 24 | Mar 2 | Mar 9 |
| 24°F65% of yrs | Dec 25 | Jan 2 | Jan 9 | Jan 18 | Jan 25 | Feb 1 | Feb 9 | Feb 18 | Feb 28 |
| 20°F24% of yrs | too rare for a date | ||||||||
| 16°F4% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Nov 1 | Nov 4 | Nov 9 | Nov 13 | Nov 16 | Nov 20 | Nov 25 | Nov 30 | Dec 5 |
| 32°F | Nov 9 | Nov 17 | Nov 22 | Nov 28 | Dec 1 | Dec 5 | Dec 10 | Dec 15 | Dec 26 |
| 28°F96% of yrs | Nov 23 | Dec 1 | Dec 7 | Dec 13 | Dec 19 | Dec 26 | Jan 1 | Jan 9 | Jan 21 |
| 24°F65% of yrs | Dec 11 | Dec 21 | Dec 27 | Jan 1 | Jan 5 | Jan 11 | Jan 19 | Feb 1 | Feb 16 |
| 20°F24% of yrs | too rare for a date | ||||||||
| 16°F4% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Canyon 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 78070 →Compare Spring Branch with another place →
Weather by month in Spring Branch
August is the warmest month at Canyon Dam, TX, averaging 96°F by day and 73°F at night; January is the coldest at 61°F and 40°F. A freezing night is all but certain in January (a 90% chance or more). From April to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 75% of years and March still brings one in 49% of years.
Warmth for growing adds up to 6,930 growing degree days a year (base 50°F), more than at 67% of the 351 Texas stations. 42% of them (2,876) have built up by the end of June, and August adds the most, 1,063. Precipitation totals 37.9 inches a year, most in October (4.9") and least in February (2.0"); May to September bring 46% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 61 | 40 | 2.4 | 91% | 7 | 118 |
| Feb | 65 | 43 | 2.0 | 75% | 4 | 171 |
| Mar | 72 | 50 | 2.8 | 49% | 1 | 350 |
| Apr | 79 | 57 | 2.9 | 3% | 0 | 531 |
| May | 85 | 65 | 4.5 | 0% | 0 | 775 |
| Jun | 91 | 71 | 4.1 | 0% | 0 | 931 |
| Jul | 94 | 73 | 2.7 | 0% | 0 | 1037 |
| Aug | 96 | 73 | 2.4 | 0% | 0 | 1063 |
| Sep | 89 | 68 | 3.9 | 0% | 0 | 864 |
| Oct | 81 | 59 | 4.9 | 3% | <1 | 624 |
| Nov | 70 | 49 | 2.9 | 44% | 2 | 318 |
| Dec | 63 | 42 | 2.4 | 88% | 5 | 149 |
Monthly normals 1991–2020 at Canyon Dam, TX (1,000 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, Blanco, TX, 14 miles north of Spring Branch and 310 feet higher, has a last frost 19 days later (March 20), a first frost 21 days earlier (November 10), a season 40 days shorter.
When it snows in Spring Branch, Texas
Measurable snow is rare here: only 1 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Spring Branch 2SE, TX, 2.6 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 78070
| When | What to do |
|---|---|
| December 21 – January 4 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| January 4 – January 18 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| February 1 – February 15 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| March 1 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by September 8 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by November 17 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| December 1 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 78070 is 13 miles from Canyon Dam, TX, which stands at 1,000 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 78133 (Canyon Lake). The 2023 USDA Plant Hardiness Zone Map lists ZIP 78070 in zone 8b, the band where the coldest night of the year averaged 15 to 20°F (-9.4 to -6.7°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.