Chambersburg, PA planting calendar
- USDA zone
- 7a0 to 5 °F
- Last frost
- Apr 18avg, 32°F
- First frost
- Oct 25avg, 32°F
- Growing season
- 188days
Chambersburg, Pennsylvania is in USDA plant hardiness zone 7a. Its average last spring frost is around April 18 and the first fall frost around October 25, giving a growing season of about 188 days (NOAA 1991–2020 normals, 32°F, median). Start tender crops like tomatoes and peppers indoors weeks before the last frost and set them out afterward; sow hardy crops such as peas, spinach, and lettuce before it. The planner below turns those frost dates into a printable per-crop planting calendar.
Chambersburg planting calendar
Each crop's windows are counted from Chambersburg's average frost dates. hatched = start seeds indoors, solid green = plant out, teal = a fall sowing, and the terracotta dot marks the estimated first harvest. Ranges are extension-guide planning guidance, not guarantees.
- Start indoors
- Plant out
- Fall sowing
- First harvest
| Crop | Frost tolerance | Start indoors | Plant out | First harvest | Fall planting |
|---|---|---|---|---|---|
| Tomato | Tender | Feb 21 – Mar 7 | Apr 25 – May 2 | Jun 24 – Jul 14 | — |
| Pepper | Very tender | Feb 7 – Feb 21 | May 2 – May 9 | Jul 1 – Jul 31 | — |
| Cucumber | Tender | Mar 21 – Mar 28 | Apr 25 – May 2 | Jun 14 – Jul 4 | — |
| Summer squash / zucchini | Tender | — | Apr 25 – May 2 | Jun 9 – Jun 24 | — |
| Bush bean | Tender | — | Apr 25 – May 2 | Jun 14 – Jun 24 | Aug 26 – Sep 5 |
| Sweet corn | Tender | — | Apr 18 – May 2 | Jun 17 – Jul 17 | — |
| Basil | Very tender | Mar 7 – Mar 21 | Apr 25 – May 2 | May 25 – Jun 9 | — |
| Lettuce | Half-hardy | Mar 7 – Mar 21 | Mar 21 – Apr 4 | May 5 – May 20 | Aug 12 – Aug 27 |
| Pea | Hardy | — | Mar 7 – Mar 21 | May 1 – May 16 | Aug 2 – Aug 17 |
| Spinach | Hardy | — | Mar 7 – Mar 21 | Apr 16 – Apr 26 | Aug 22 – Sep 1 |
| Carrot | Half-hardy | — | Mar 28 – Apr 4 | May 27 – Jun 16 | Jul 23 – Aug 12 |
| Broccoli | Half-hardy | Feb 21 – Mar 7 | Mar 21 – Apr 4 | May 15 – Jun 4 | Jul 28 – Aug 17 |
Data: NOAA NCEI U.S. Climate Normals 1991–2020 (public domain) and USDA Plant Hardiness Zone Map 2023. Planting windows synthesized from U.S. Cooperative Extension guides.
Frost & freeze dates
From NOAA's 1991–2020 Climate Normals at station USC00361354. The median (p50) is the average date; the 90%-safe column is the date the freeze has passed in about 9 years out of 10 (p10 for spring, p90 for fall) — the conservative date to plant after or harvest before.
| Threshold | Last spring — avg | Last spring — 90%-safe | First fall — avg | First fall — 90%-safe | Season (days) |
|---|---|---|---|---|---|
| 36°F | Apr 30 | May 17 | Oct 14 | Oct 28 | 165 |
| 32°F (freeze) | Apr 18 | May 5 | Oct 25 | Nov 8 | 188 |
| 28°F | Apr 4 | Apr 21 | Nov 6 | Nov 21 | 213 |
| 24°F | Mar 24 | Apr 6 | Nov 18 | Dec 5 | 238 |
32°F is the standard "freeze" line that damages tender crops; lighter 36°F frost can nip the most cold-sensitive plants, while hardy crops shrug off light frost down toward 28°F. Use the threshold that matches what you are protecting.
Growing degree days
Growing degree days (GDD) accumulate warmth above a base temperature over the year — a better predictor of crop development than the calendar alone. Warm-season crops need a long, warm GDD total; a short, cool GDD total favors greens and brassicas.
| Model | °F·days | Used for |
|---|---|---|
| Base 50°F (warm-season) | 3,351 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 5,695 | cool-season crops (brassicas, greens) |
Hardiness zone 7a
Chambersburg sits in USDA plant hardiness zone 7a on the 2023 map — meaning its average annual extreme minimum winter temperature is about 0 to 5 °F. That number tells you which perennials, shrubs, and trees reliably survive an average winter here; it does not set your planting dates, which come from the frost calendar above.
Explore more places in zone 7a, or see all USDA hardiness zones.
Frequently asked questions
- What USDA hardiness zone is Chambersburg?
- Chambersburg, Pennsylvania is in USDA plant hardiness zone 7a on the 2023 map (average annual extreme minimum temperature 0 to 5 °F) — from the USDA Plant Hardiness Zone Map 2023, matched to this location's ZIP. See the methodology page for sources.
- When is the last frost in Chambersburg?
- The average (median) last spring frost at 32°F is around April 18, from NOAA's 1991–2020 climate normals at the nearest reporting station. Roughly one year in ten the last frost is as late as May 5, so wait until then before setting out frost-tender plants if you want to be safe.
- When is the first fall frost in Chambersburg?
- The average first fall frost at 32°F is around October 25. That leaves a growing season of about 188 days between the average last spring and first fall frosts.
- When should I start tomatoes in Chambersburg?
- Start tomato seeds indoors about Feb 21 – Mar 7 and transplant them outside about Apr 25 – May 2, once the danger of frost has passed. Estimated first harvest is around Jun 24 – Jul 14.
- How long is the growing season in Chambersburg?
- About 188 days at the 32°F threshold (NOAA 1991–2020, median) — the span between the average last spring frost (~April 18) and the average first fall frost (~October 25). Cold-hardy crops extend usable time at both ends; frost-tender crops fit inside it.
Sources & method
Frost, freeze, growing-season, and growing-degree-day figures are NOAA NCEI U.S. Climate Normals 1991–2020 for station USC00361354 (Chambersburg 1 Ese, 3.1 km away). The hardiness zone is the USDA Plant Hardiness Zone Map 2023, matched to this location's ZIP. Planting windows are computed by counting from the average last and first frost using per-crop offsets synthesized from U.S. Cooperative Extension guides — the full method and citations are on the methodology page.