USDA Hardiness Zone 7a
Frost Dates for 19335 — Downingtown, Pennsylvania
NOAA 1991–2020 normals from Glenmoore, PA (500 ft), 5 miles north.
Updated
In Downingtown, the last spring frost (32°F) is around April 11 in half of years and has passed by April 29 in nine years out of ten. The first fall frost comes around November 1, as early as October 16 one year in ten, leaving a typical freeze-free season of 205 days (NOAA, Glenmoore, PA).
- Last spring frost
- April 11
- First fall frost
- November 1
- Growing season
- 205 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 6
- Last snow
- March 24
- Winters with snow
- 100%
- Snow per year
- 28.4"
median, 1991–2020
median, 1991–2020
30 of 30 observed
NOAA normal
Frost risk by date in Downingtown
Half of springs at Glenmoore, PA see their last 32°F night by April 11; only one in ten is past it by March 28, and one in ten still has one after April 29. Planting tender crops after April 17 leaves a 30% risk of a frost on them, after April 21 20%, and after April 29 10%. The 18 days between the even-odds date and the one-in-ten date is wider than at 70% of the 176 Pennsylvania stations behind this site's ZIP pages.
In fall the first 32°F night comes by November 1 in half of years, as early as October 16 one year in ten, and holds off past November 17 one year in ten. A hard freeze of 28°F follows 14 days later, around November 15; in spring the one-in-ten date for 28°F is April 11, 18 days before the 32°F one. The freeze-free season lasts 205 days in a typical year, longer than at 92% of the 176 Pennsylvania stations; it reaches 225 days one year in ten and falls short of 182 one year in ten. On average 107 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 15 days longer, to about April 26, and return around October 19. Severe cold of 16°F or below comes every winter, usually between December 30 and February 28.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 12 | Apr 16 | Apr 20 | Apr 22 | Apr 26 | Apr 30 | May 1 | May 5 | May 11 |
| 32°F | Mar 28 | Apr 1 | Apr 5 | Apr 8 | Apr 11 | Apr 14 | Apr 17 | Apr 21 | Apr 29 |
| 28°F | Mar 15 | Mar 20 | Mar 24 | Mar 27 | Mar 31 | Apr 1 | Apr 4 | Apr 6 | Apr 11 |
| 24°F | Mar 2 | Mar 8 | Mar 12 | Mar 16 | Mar 19 | Mar 21 | Mar 24 | Mar 27 | Mar 31 |
| 20°F | Feb 21 | Feb 27 | Mar 2 | Mar 6 | Mar 8 | Mar 12 | Mar 15 | Mar 18 | Mar 22 |
| 16°F | Feb 2 | Feb 12 | Feb 19 | Feb 24 | Feb 28 | Mar 3 | Mar 6 | Mar 10 | Mar 15 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 6 | Oct 10 | Oct 13 | Oct 16 | Oct 19 | Oct 23 | Oct 26 | Oct 30 | Nov 3 |
| 32°F | Oct 16 | Oct 22 | Oct 27 | Oct 30 | Nov 1 | Nov 4 | Nov 7 | Nov 11 | Nov 17 |
| 28°F | Oct 31 | Nov 5 | Nov 9 | Nov 12 | Nov 15 | Nov 19 | Nov 22 | Nov 27 | Dec 3 |
| 24°F | Nov 12 | Nov 18 | Nov 22 | Nov 26 | Dec 1 | Dec 2 | Dec 6 | Dec 12 | Dec 20 |
| 20°F | Nov 23 | Dec 1 | Dec 4 | Dec 8 | Dec 14 | Dec 19 | Dec 24 | Dec 28 | Jan 5 |
| 16°F | Dec 7 | Dec 14 | Dec 21 | Dec 26 | Dec 30 | Jan 2 | Jan 7 | Jan 14 | Jan 22 |
Freeze probabilities 1991–2020 at Glenmoore, 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 19335 →Compare Downingtown with another place →
Compared with the next station
The nearest other station, W Chester 2 NW, PA, 6 miles southeast of Downingtown, has a last frost 15 days later (April 26), a first frost 14 days earlier (October 18), a season 31 days shorter.
When it snows in Downingtown, Pennsylvania
The first measurable snow (0.1 inch or more) in Downingtown usually arrives around December 6, and the last of the season around March 24. Those are the middle dates across the winters of 1991–2020 at Glenmoore, PA, 5.4 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 18 days after the last snow.
Planting calendar for 19335
| When | What to do |
|---|---|
| January 31 – February 14 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| February 14 – February 28 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 14 – March 28 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 11 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 9 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 18 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| November 1 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 19335 is 5 miles from Glenmoore, PA, which stands at 500 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 19335 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.