USDA Hardiness Zone 6b
Frost Dates for 15065 — Natrona Heights, Pennsylvania
NOAA 1991–2020 normals from Natrona Lock 4, PA (760 ft), 1 miles south.
Updated
In Natrona Heights, the last spring frost (32°F) is around April 16 in half of years and has passed by May 2 in nine years out of ten. The first fall frost comes around November 2, as early as October 20 one year in ten, leaving a typical freeze-free season of 199 days (NOAA, Natrona Lock 4, PA).
- Last spring frost
- April 16
- First fall frost
- November 2
- Growing season
- 199 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 5
- Last snow
- March 6
- Winters with snow
- 81%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
21 of 26 observed
NOAA normal
Frost risk by date in Natrona Heights
Half of springs at Natrona Lock 4, PA see their last 32°F night by April 16; only one in ten is past it by March 31, and one in ten still has one after May 2. Planting tender crops after April 21 leaves a 30% risk of a frost on them, after April 26 20%, and after May 2 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 51% of the 176 Pennsylvania stations behind this site's ZIP pages.
In fall the first 32°F night comes by November 2 in half of years, as early as October 20 one year in ten, and holds off past November 16 one year in ten. A hard freeze of 28°F follows 12 days later, around November 14; in spring the one-in-ten date for 28°F is April 16, 16 days before the 32°F one. The freeze-free season lasts 199 days in a typical year, longer than at 89% of the 176 Pennsylvania stations; it reaches 218 days one year in ten and falls short of 178 one year in ten. On average 117 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 April 29, and return around October 21. Severe cold of 16°F or below comes every winter, usually between December 20 and March 5.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 14 | Apr 19 | Apr 22 | Apr 25 | Apr 29 | May 2 | May 5 | May 10 | May 16 |
| 32°F | Mar 31 | Apr 5 | Apr 9 | Apr 12 | Apr 16 | Apr 18 | Apr 21 | Apr 26 | May 2 |
| 28°F | Mar 19 | Mar 25 | Mar 29 | Apr 1 | Apr 3 | Apr 5 | Apr 8 | Apr 12 | Apr 16 |
| 24°F | Mar 10 | Mar 15 | Mar 18 | Mar 20 | Mar 25 | Mar 28 | Mar 30 | Apr 2 | Apr 6 |
| 20°F | Feb 27 | Mar 4 | Mar 8 | Mar 12 | Mar 15 | Mar 18 | Mar 21 | Mar 25 | Mar 29 |
| 16°F | Feb 11 | Feb 19 | Feb 26 | Mar 2 | Mar 5 | Mar 9 | Mar 12 | Mar 16 | Mar 21 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 7 | Oct 12 | Oct 15 | Oct 18 | Oct 21 | Oct 23 | Oct 26 | Oct 30 | Nov 3 |
| 32°F | Oct 20 | Oct 24 | Oct 28 | Oct 31 | Nov 2 | Nov 5 | Nov 8 | Nov 11 | Nov 16 |
| 28°F | Nov 2 | Nov 5 | Nov 9 | Nov 11 | Nov 14 | Nov 16 | Nov 20 | Nov 24 | Dec 1 |
| 24°F | Nov 9 | Nov 14 | Nov 18 | Nov 21 | Nov 25 | Nov 28 | Dec 1 | Dec 6 | Dec 12 |
| 20°F | Nov 19 | Nov 25 | Nov 30 | Dec 3 | Dec 7 | Dec 10 | Dec 15 | Dec 20 | Dec 27 |
| 16°F | Dec 1 | Dec 6 | Dec 11 | Dec 16 | Dec 20 | Dec 24 | Dec 29 | Jan 1 | Jan 10 |
Freeze probabilities 1991–2020 at Natrona Lock 4, 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 15065 →Compare Natrona Heights with another place →
Compared with the next station
The nearest other station, Schenley Lock 5, PA, 5 miles northeast of Natrona Heights, has a last frost 5 days later (April 21), a first frost 3 days earlier (October 30), a season 9 days shorter.
When it snows in Natrona Heights, Pennsylvania
The first measurable snow (0.1 inch or more) in Natrona Heights usually arrives around December 5, and the last of the season around March 6. Those are the middle dates across the winters of 1991–2020 at Natrona Lock 4, PA, 1 miles away: half of years saw snow earlier, half later. Snow fell in 81% of those winters. The last 32°F night of spring typically comes 41 days after the last snow.
Planting calendar for 15065
| When | What to do |
|---|---|
| February 5 – February 19 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 19 – March 5 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 19 – April 2 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 16 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 10 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 19 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 2 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 15065 is 1 mile from Natrona Lock 4, PA, which stands at 760 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 15068 (New Kensington). The 2023 USDA Plant Hardiness Zone Map lists ZIP 15065 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.