USDA Hardiness Zone 7a
Frost Dates for 17362 — Spring Grove, Pennsylvania
NOAA 1991–2020 normals from York Airport, PA (486 ft), 4 miles north.
Updated
In Spring Grove, the last spring frost (32°F) is around April 27 in half of years and has passed by May 11 in nine years out of ten. The first fall frost comes around October 18, as early as October 4 one year in ten, leaving a typical freeze-free season of 174 days (NOAA, York Airport, PA).
- Last spring frost
- April 27
- First fall frost
- October 18
- Growing season
- 174 days
- Hardiness zone
- 7a
50% probability
50% probability
freeze-free, 50%
0 to 5°F (-17.8 to -15.0°C) coldest night
- First snow
- December 11
- Last snow
- March 14
- Winters with snow
- 100%
- Snow per year
- 28.8"
median, 1991–2020
median, 1991–2020
29 of 29 observed
NOAA normal
Frost risk by date in Spring Grove
Half of springs at York Airport, PA see their last 32°F night by April 27; only one in ten is past it by April 12, and one in ten still has one after May 11. Planting tender crops after May 3 leaves a 30% risk of a frost on them, after May 7 20%, and after May 11 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 86% of the 176 Pennsylvania stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 18 in half of years, as early as October 4 one year in ten, and holds off past November 1 one year in ten. A hard freeze of 28°F follows 12 days later, around October 30; in spring the one-in-ten date for 28°F is April 29, 12 days before the 32°F one. The freeze-free season lasts 174 days in a typical year, shorter than at 52% of the 176 Pennsylvania stations; it reaches 194 days one year in ten and falls short of 153 one year in ten. On average 125 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 May 8, and return around October 7. Severe cold of 16°F or below comes every winter, usually between December 7 and March 9.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 24 | Apr 28 | May 1 | May 4 | May 8 | May 10 | May 14 | May 18 | May 23 |
| 32°F | Apr 12 | Apr 17 | Apr 21 | Apr 24 | Apr 27 | Apr 30 | May 3 | May 7 | May 11 |
| 28°F | Mar 30 | Apr 3 | Apr 6 | Apr 10 | Apr 12 | Apr 16 | Apr 18 | Apr 23 | Apr 29 |
| 24°F | Mar 15 | Mar 23 | Mar 27 | Mar 30 | Apr 1 | Apr 3 | Apr 6 | Apr 9 | Apr 14 |
| 20°F | Mar 5 | Mar 10 | Mar 14 | Mar 17 | Mar 21 | Mar 24 | Mar 27 | Mar 31 | Apr 3 |
| 16°F | Feb 21 | Feb 27 | Mar 2 | Mar 6 | Mar 9 | Mar 13 | Mar 16 | Mar 20 | Mar 26 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 26 | Sep 30 | Oct 2 | Oct 4 | Oct 7 | Oct 9 | Oct 12 | Oct 15 | Oct 20 |
| 32°F | Oct 4 | Oct 8 | Oct 12 | Oct 15 | Oct 18 | Oct 21 | Oct 25 | Oct 29 | Nov 1 |
| 28°F | Oct 13 | Oct 19 | Oct 23 | Oct 27 | Oct 30 | Nov 1 | Nov 3 | Nov 6 | Nov 11 |
| 24°F | Oct 25 | Oct 31 | Nov 3 | Nov 6 | Nov 9 | Nov 12 | Nov 15 | Nov 19 | Nov 26 |
| 20°F | Nov 6 | Nov 11 | Nov 15 | Nov 18 | Nov 22 | Nov 25 | Nov 29 | Dec 4 | Dec 11 |
| 16°F | Nov 18 | Nov 26 | Dec 1 | Dec 3 | Dec 7 | Dec 11 | Dec 16 | Dec 21 | Dec 27 |
Freeze probabilities 1991–2020 at York Airport, 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 17362 →Compare Spring Grove with another place →
Weather by month in Spring Grove
July is the warmest month at York Airport, PA, averaging 85°F by day and 63°F at night; January is the coldest at 39°F and 21°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 37% of years.
Warmth for growing adds up to 3,226 growing degree days a year (base 50°F), more than at 74% of the 176 Pennsylvania stations. 35% of them (1,116) have built up by the end of June, and July adds the most, 749. Precipitation totals 42.3 inches a year, most in September (4.8") and least in February (2.5"); May to September bring 48% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 39 | 21 | 2.6 | 100% | 27 | 4 |
| Feb | 42 | 22 | 2.5 | 100% | 24 | 4 |
| Mar | 51 | 29 | 3.7 | 100% | 20 | 28 |
| Apr | 63 | 39 | 3.4 | 98% | 7 | 123 |
| May | 73 | 50 | 4.2 | 37% | 1 | 350 |
| Jun | 81 | 59 | 3.2 | 0% | 0 | 606 |
| Jul | 85 | 63 | 4.3 | 0% | 0 | 749 |
| Aug | 84 | 61 | 3.8 | 0% | 0 | 688 |
| Sep | 77 | 54 | 4.8 | 2% | <1 | 460 |
| Oct | 66 | 42 | 3.6 | 85% | 5 | 171 |
| Nov | 54 | 33 | 3.1 | 100% | 17 | 34 |
| Dec | 44 | 25 | 3.1 | 100% | 25 | 9 |
Monthly normals 1991–2020 at York Airport, PA (486 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, York 3 SSW Pump Stn, PA, 8 miles northeast of Spring Grove, has a last frost 1 day earlier (April 26), a first frost 1 day later (October 19), a season 3 days longer.
When it snows in Spring Grove, Pennsylvania
The first measurable snow (0.1 inch or more) in Spring Grove usually arrives around December 11, and the last of the season around March 14. Those are the middle dates across the winters of 1991–2020 at Spring Grove, PA, 1.2 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 44 days after the last snow.
Planting calendar for 17362
| When | What to do |
|---|---|
| February 16 – March 2 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 2 – March 16 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 30 – April 13 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 27 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 26 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 4 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 18 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 17362 is 4 miles from York Airport, PA, which stands at 486 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 17315 (Dover). The 2023 USDA Plant Hardiness Zone Map lists ZIP 17362 in zone 7a, the band where the coldest night of the year averaged 0 to 5°F (-17.8 to -15.0°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.