USDA Hardiness Zone 9a
Frost Dates for 77302 — Conroe, Texas
NOAA 1991–2020 normals from Conroe Montgomery Co Airport, TX (245 ft), 8 miles north.
Updated
In Conroe, the last spring frost (32°F) is around March 11 in half of years and has passed by April 3 in nine years out of ten. The first fall frost comes around November 19, as early as November 1 one year in ten, leaving a typical freeze-free season of 253 days (NOAA, Conroe Montgomery Co Airport, TX).
- Last spring frost
- March 11
- First fall frost
- November 19
- Growing season
- 253 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
- —
median, 1991–2020
median, 1991–2020
0 of 20 observed
NOAA normal
Frost risk by date in Conroe
Half of springs at Conroe Montgomery Co Airport, TX see their last 32°F night by March 11; only one in ten is past it by February 14, and one in ten still has one after April 3. Planting tender crops after March 21 leaves a 30% risk of a frost on them, after March 27 20%, and after April 3 10%. The 23 days between the even-odds date and the one-in-ten date is wider than at 72% 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 November 19 in half of years, as early as November 1 one year in ten, and holds off past December 9 one year in ten. A hard freeze of 28°F follows 15 days later, around December 4; in spring the one-in-ten date for 28°F is March 18, 16 days before the 32°F one. The freeze-free season lasts 253 days in a typical year, longer than at 56% of the 339 Texas stations; it reaches 286 days one year in ten and falls short of 224 one year in ten. On average 27 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 13 days longer, to about March 24, and return around November 8. Nights of 24°F, cold enough to damage hardier plants, come in 83% of winters and 16°F in 9%.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Mar 3 | Mar 10 | Mar 15 | Mar 19 | Mar 24 | Mar 29 | Apr 2 | Apr 7 | Apr 15 |
| 32°F | Feb 14 | Feb 24 | Mar 1 | Mar 6 | Mar 11 | Mar 15 | Mar 21 | Mar 27 | Apr 3 |
| 28°F | Jan 22 | Jan 29 | Feb 6 | Feb 14 | Feb 21 | Feb 28 | Mar 4 | Mar 10 | Mar 18 |
| 24°F83% of yrs | Dec 28 | Jan 9 | Jan 18 | Jan 24 | Jan 30 | Feb 5 | Feb 16 | Feb 27 | Mar 8 |
| 20°F38% of yrs | too rare for a date | ||||||||
| 16°F9% of yrs | too rare for a date | ||||||||
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 24 | Oct 29 | Nov 1 | Nov 4 | Nov 8 | Nov 11 | Nov 14 | Nov 19 | Nov 26 |
| 32°F | Nov 1 | Nov 5 | Nov 10 | Nov 14 | Nov 19 | Nov 24 | Nov 29 | Dec 3 | Dec 9 |
| 28°F | Nov 11 | Nov 19 | Nov 25 | Dec 1 | Dec 4 | Dec 10 | Dec 20 | Dec 29 | Jan 8 |
| 24°F83% of yrs | Nov 30 | Dec 7 | Dec 14 | Dec 24 | Jan 1 | Jan 4 | Jan 9 | Jan 17 | Feb 3 |
| 20°F38% of yrs | too rare for a date | ||||||||
| 16°F9% of yrs | too rare for a date | ||||||||
Freeze probabilities 1991–2020 at Conroe Montgomery Co Airport, 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 77302 →Compare Conroe with another place →
Weather by month in Conroe
August is the warmest month at Conroe Montgomery Co Airport, TX, averaging 95°F by day and 72°F at night; January is the coldest at 62°F and 39°F. A freezing night is all but certain in every month from December to January (a 90% chance or more). From May to October the chance of a 32°F night stays under 10% each month. In spring, February still brings one in 84% of years and March still brings one in 67% of years and April still brings one in 14% of years.
Warmth for growing adds up to 6,776 growing degree days a year (base 50°F), more than at 64% of the 351 Texas stations. 42% of them (2,863) have built up by the end of June, and August adds the most, 1,024. Precipitation totals 47.7 inches a year, most in October (5.5") and least in February (2.9"); May to September bring 42% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 62 | 39 | 4.3 | 96% | 10 | 131 |
| Feb | 66 | 43 | 2.9 | 84% | 5 | 180 |
| Mar | 73 | 49 | 3.0 | 67% | 2 | 355 |
| Apr | 79 | 55 | 3.1 | 14% | <1 | 511 |
| May | 86 | 64 | 4.8 | 0% | 0 | 769 |
| Jun | 91 | 70 | 4.4 | 0% | 0 | 918 |
| Jul | 94 | 72 | 3.2 | 0% | 0 | 1018 |
| Aug | 95 | 72 | 3.9 | 0% | 0 | 1024 |
| Sep | 90 | 66 | 3.6 | 0% | 0 | 840 |
| Oct | 82 | 56 | 5.5 | 8% | <1 | 588 |
| Nov | 71 | 47 | 5.1 | 70% | 3 | 287 |
| Dec | 64 | 41 | 3.9 | 94% | 8 | 155 |
Monthly normals 1991–2020 at Conroe Montgomery Co Airport, TX (245 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, Conroe, TX, 8 miles northwest of Conroe, has a last frost 15 days earlier (February 24), a first frost 13 days later (December 2), a season 32 days longer.
When it snows in Conroe, Texas
Measurable snow is rare here: only 0 of 20 winters from 1991 to 2020 recorded 0.1 inch or more at Conroe, TX, 8.5 miles away, so there is no typical first-snow date to plan around.
Planting calendar for 77302
| When | What to do |
|---|---|
| December 31 – January 14 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| January 14 – January 28 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| February 11 – February 25 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| March 11 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 27 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by November 5 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 19 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 77302 is 8 miles from Conroe Montgomery Co Airport, TX, which stands at 245 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station; its figures are presented in full for 77303 (Conroe). The 2023 USDA Plant Hardiness Zone Map lists ZIP 77302 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.