USDA Hardiness Zone 6b
Frost Dates for 15342 — Houston, Pennsylvania
NOAA 1991–2020 normals from Washington 3 NE, PA (1,300 ft), 5 miles south.
Updated
In Houston, the last spring frost (32°F) is around April 24 in half of years and has passed by May 18 in nine years out of ten. The first fall frost comes around October 23, as early as October 8 one year in ten, leaving a typical freeze-free season of 181 days (NOAA, Washington 3 NE, PA).
- Last spring frost
- April 24
- First fall frost
- October 23
- Growing season
- 181 days
- Hardiness zone
- 6b
50% probability
50% probability
freeze-free, 50%
-5 to 0°F (-20.6 to -17.8°C) coldest night
- First snow
- December 1
- Last snow
- March 30
- Winters with snow
- 100%
- Snow per year
- 31.9"
median, 1991–2020
median, 1991–2020
24 of 24 observed
NOAA normal
Frost risk by date in Houston
Half of springs at Washington 3 NE, PA see their last 32°F night by April 24; only one in ten is past it by April 8, and one in ten still has one after May 18. Planting tender crops after May 3 leaves a 30% risk of a frost on them, after May 10 20%, and after May 18 10%. The 24 days between the even-odds date and the one-in-ten date is the widest of the 176 Pennsylvania 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 October 23 in half of years, as early as October 8 one year in ten, and holds off past November 5 one year in ten. A hard freeze of 28°F follows 10 days later, around November 2; in spring the one-in-ten date for 28°F is May 4, 14 days before the 32°F one. The freeze-free season lasts 181 days in a typical year, longer than at 65% of the 176 Pennsylvania stations; it reaches 203 days one year in ten and falls short of 158 one year in ten. On average 122 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 12 days longer, to about May 6, and return around October 11. Severe cold of 16°F or below comes every winter, usually between December 8 and March 14.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 19 | Apr 24 | Apr 29 | May 2 | May 6 | May 11 | May 15 | May 20 | May 25 |
| 32°F | Apr 8 | Apr 13 | Apr 17 | Apr 21 | Apr 24 | Apr 30 | May 3 | May 10 | May 18 |
| 28°F | Mar 29 | Apr 2 | Apr 5 | Apr 8 | Apr 11 | Apr 15 | Apr 19 | Apr 24 | May 4 |
| 24°F | Mar 16 | Mar 22 | Mar 26 | Mar 30 | Apr 1 | Apr 3 | Apr 6 | Apr 10 | Apr 16 |
| 20°F | Mar 6 | Mar 12 | Mar 16 | Mar 19 | Mar 23 | Mar 26 | Mar 29 | Apr 1 | Apr 5 |
| 16°F | Feb 24 | Mar 1 | Mar 7 | Mar 10 | Mar 14 | Mar 17 | Mar 20 | Mar 25 | Mar 29 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 29 | Oct 2 | Oct 5 | Oct 8 | Oct 11 | Oct 14 | Oct 17 | Oct 20 | Oct 25 |
| 32°F | Oct 8 | Oct 13 | Oct 17 | Oct 20 | Oct 23 | Oct 26 | Oct 29 | Nov 1 | Nov 5 |
| 28°F | Oct 19 | Oct 24 | Oct 28 | Nov 1 | Nov 2 | Nov 5 | Nov 8 | Nov 11 | Nov 16 |
| 24°F | Nov 1 | Nov 4 | Nov 7 | Nov 10 | Nov 14 | Nov 17 | Nov 21 | Nov 27 | Dec 2 |
| 20°F | Nov 7 | Nov 12 | Nov 17 | Nov 21 | Nov 27 | Dec 1 | Dec 3 | Dec 8 | Dec 16 |
| 16°F | Nov 16 | Nov 25 | Dec 1 | Dec 4 | Dec 8 | Dec 13 | Dec 19 | Dec 25 | Jan 1 |
Freeze probabilities 1991–2020 at Washington 3 NE, PA, 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 15342 →Compare Houston with another place →
Weather by month in Houston
July is the warmest month at Washington 3 NE, PA, averaging 83°F by day and 62°F at night; January is the coldest at 37°F and 20°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 36% of years.
Warmth for growing adds up to 3,122 growing degree days a year (base 50°F), more than at 62% of the 176 Pennsylvania stations. 35% of them (1,092) have built up by the end of June, and July adds the most, 699. Precipitation totals 41.3 inches a year, most in June (4.5") and least in February (2.5"); May to September bring 47% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 37 | 20 | 3.3 | 100% | 27 | 5 |
| Feb | 40 | 22 | 2.5 | 100% | 24 | 5 |
| Mar | 49 | 29 | 3.5 | 100% | 20 | 38 |
| Apr | 63 | 40 | 3.3 | 96% | 7 | 140 |
| May | 72 | 49 | 4.1 | 36% | 1 | 338 |
| Jun | 80 | 58 | 4.5 | 0% | <1 | 566 |
| Jul | 83 | 62 | 3.6 | 0% | 0 | 699 |
| Aug | 83 | 60 | 3.5 | 0% | 0 | 663 |
| Sep | 76 | 54 | 3.6 | 0% | 0 | 446 |
| Oct | 64 | 43 | 3.0 | 78% | 4 | 170 |
| Nov | 52 | 33 | 3.1 | 100% | 15 | 41 |
| Dec | 41 | 26 | 3.3 | 100% | 25 | 11 |
Monthly normals 1991–2020 at Washington 3 NE, PA (1,300 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, Pittsburgh International Airport, PA, 17 miles north of Houston, has a last frost 1 day earlier (April 23), the same first-frost date.
When it snows in Houston, Pennsylvania
The first measurable snow (0.1 inch or more) in Houston usually arrives around December 1, and the last of the season around March 30. Those are the middle dates across the winters of 1991–2020 at Washington 3 NE, PA, 4.6 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 25 days after the last snow.
Planting calendar for 15342
| When | What to do |
|---|---|
| February 13 – February 27 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 27 – March 13 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 27 – April 10 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 24 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 31 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 9 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 23 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 15342 is 5 miles from Washington 3 NE, PA, which stands at 1,300 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 5 other ZIP codes share the station; its figures are presented in full for 15301 (Washington). The 2023 USDA Plant Hardiness Zone Map lists ZIP 15342 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.
Frost dates across Pennsylvania →
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.