USDA Hardiness Zone 6a
Frost Dates for 16327 — Guys Mills, Pennsylvania
NOAA 1991–2020 normals from Titusville Wtr Wks, PA (1,220 ft), 13 miles east.
Updated
In Guys Mills, the last spring frost (32°F) is around May 12 in half of years and has passed by May 28 in nine years out of ten. The first fall frost comes around October 10, as early as September 25 one year in ten, leaving a typical freeze-free season of 149 days (NOAA, Titusville Wtr Wks, PA).
- Last spring frost
- May 12
- First fall frost
- October 10
- Growing season
- 149 days
- Hardiness zone
- 6a
50% probability
50% probability
freeze-free, 50%
-10 to -5°F (-23.3 to -20.6°C) coldest night
- First snow
- November 8
- Last snow
- April 5
- Winters with snow
- 100%
- Snow per year
- 89.4"
median, 1991–2020
median, 1991–2020
29 of 29 observed
NOAA normal
Frost risk by date in Guys Mills
Half of springs at Titusville Wtr Wks, PA see their last 32°F night by May 12; only one in ten is past it by April 29, and one in ten still has one after May 28. Planting tender crops after May 19 leaves a 30% risk of a frost on them, after May 23 20%, and after May 28 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 October 10 in half of years, as early as September 25 one year in ten, and holds off past October 23 one year in ten. A hard freeze of 28°F follows 11 days later, around October 21; in spring the one-in-ten date for 28°F is May 19, 9 days before the 32°F one. The freeze-free season lasts 149 days in a typical year, shorter than at 88% of the 176 Pennsylvania stations; it reaches 169 days one year in ten and falls short of 126 one year in ten. On average 161 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 May 25, and return around September 29. Severe cold of 16°F or below comes every winter, usually between November 25 and March 30.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 10 | May 15 | May 19 | May 22 | May 25 | May 28 | May 31 | Jun 2 | Jun 7 |
| 32°F | Apr 29 | May 2 | May 6 | May 9 | May 12 | May 16 | May 19 | May 23 | May 28 |
| 28°F | Apr 17 | Apr 22 | Apr 26 | Apr 29 | May 1 | May 4 | May 8 | May 12 | May 19 |
| 24°F | Apr 6 | Apr 10 | Apr 15 | Apr 18 | Apr 21 | Apr 23 | Apr 27 | Apr 30 | May 6 |
| 20°F | Mar 25 | Mar 31 | Apr 3 | Apr 5 | Apr 8 | Apr 12 | Apr 15 | Apr 18 | Apr 22 |
| 16°F | Mar 14 | Mar 19 | Mar 23 | Mar 26 | Mar 30 | Apr 1 | Apr 4 | Apr 7 | Apr 14 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 14 | Sep 20 | Sep 24 | Sep 27 | Sep 29 | Oct 1 | Oct 3 | Oct 7 | Oct 11 |
| 32°F | Sep 25 | Oct 1 | Oct 3 | Oct 6 | Oct 10 | Oct 12 | Oct 15 | Oct 18 | Oct 23 |
| 28°F | Oct 4 | Oct 11 | Oct 15 | Oct 18 | Oct 21 | Oct 24 | Oct 28 | Nov 1 | Nov 5 |
| 24°F | Oct 18 | Oct 23 | Oct 28 | Nov 1 | Nov 2 | Nov 5 | Nov 8 | Nov 12 | Nov 17 |
| 20°F | Nov 1 | Nov 4 | Nov 7 | Nov 11 | Nov 14 | Nov 18 | Nov 21 | Nov 24 | Nov 29 |
| 16°F | Nov 8 | Nov 14 | Nov 18 | Nov 21 | Nov 25 | Nov 28 | Dec 1 | Dec 5 | Dec 11 |
Freeze probabilities 1991–2020 at Titusville Wtr Wks, 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 16327 →Compare Guys Mills with another place →
Weather by month in Guys Mills
July is the warmest month at Titusville Wtr Wks, PA, averaging 81°F by day and 57°F at night; January is the coldest at 33°F and 15°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 85% of years.
Warmth for growing adds up to 2,326 growing degree days a year (base 50°F), fewer than at 86% of the 176 Pennsylvania stations. 33% of them (759) have built up by the end of June, and July adds the most, 584. Precipitation totals 46.4 inches a year, most in June (4.9") and least in February (2.7"); May to September bring 45% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 33 | 15 | 3.5 | 100% | 29 | 2 |
| Feb | 35 | 14 | 2.7 | 100% | 26 | 1 |
| Mar | 44 | 22 | 3.5 | 100% | 26 | 10 |
| Apr | 58 | 33 | 4.2 | 100% | 16 | 62 |
| May | 69 | 43 | 4.1 | 85% | 4 | 235 |
| Jun | 77 | 53 | 4.9 | 5% | 0 | 450 |
| Jul | 81 | 57 | 4.3 | 0% | 0 | 584 |
| Aug | 80 | 55 | 3.6 | 0% | 0 | 536 |
| Sep | 73 | 49 | 4.1 | 19% | 1 | 338 |
| Oct | 61 | 38 | 4.2 | 97% | 10 | 94 |
| Nov | 48 | 29 | 3.6 | 100% | 21 | 13 |
| Dec | 37 | 21 | 3.7 | 100% | 28 | 2 |
Monthly normals 1991–2020 at Titusville Wtr Wks, PA (1,220 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, Port Meadville Airport, PA, 14 miles west of Guys Mills and 180 feet higher, has a last frost 12 days earlier (April 30), a first frost 13 days later (October 23), a season 26 days longer.
When it snows in Guys Mills, Pennsylvania
The first measurable snow (0.1 inch or more) in Guys Mills usually arrives around November 8, and the last of the season around April 5. Those are the middle dates across the winters of 1991–2020 at Titusville Wtr Wks, PA, 13.3 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 37 days after the last snow.
Planting calendar for 16327
| When | What to do |
|---|---|
| March 3 – March 17 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 17 – March 31 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 14 – April 28 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 12 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 18 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 26 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 10 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 16327 is 13 miles from Titusville Wtr Wks, PA, which stands at 1,220 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 16354 (Titusville). The 2023 USDA Plant Hardiness Zone Map lists ZIP 16327 in zone 6a, the band where the coldest night of the year averaged -10 to -5°F (-23.3 to -20.6°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.