Carpenter, WY 82054 planting calendar
- USDA zone
- 5b−15 to −10 °F
- Last frost
- May 14avg, 32°F
- First frost
- Sep 26avg, 32°F
- Growing season
- 133days
Carpenter, Wyoming is in USDA plant hardiness zone 5b. Its average last spring frost is around May 14 and the first fall frost around September 26, giving a growing season of about 133 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.
Carpenter planting calendar
Each crop's windows are counted from Carpenter'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 | Mar 19 – Apr 2 | May 21 – May 28 | Jul 20 – Aug 9 | — |
| Pepper | Very tender | Mar 5 – Mar 19 | May 28 – Jun 4 | Jul 27 – Aug 26 | — |
| Cucumber | Tender | Apr 16 – Apr 23 | May 21 – May 28 | Jul 10 – Jul 30 | — |
| Summer squash / zucchini | Tender | — | May 21 – May 28 | Jul 5 – Jul 20 | — |
| Bush bean | Tender | — | May 21 – May 28 | Jul 10 – Jul 20 | Jul 28 – Aug 7 |
| Sweet corn | Tender | — | May 14 – May 28 | Jul 13 – Aug 12 | — |
| Basil | Very tender | Apr 2 – Apr 16 | May 21 – May 28 | Jun 20 – Jul 5 | — |
| Lettuce | Half-hardy | Apr 2 – Apr 16 | Apr 16 – Apr 30 | May 31 – Jun 15 | Jul 14 – Jul 29 |
| Pea | Hardy | — | Apr 2 – Apr 16 | May 27 – Jun 11 | Jul 4 – Jul 19 |
| Spinach | Hardy | — | Apr 2 – Apr 16 | May 12 – May 22 | Jul 24 – Aug 3 |
| Carrot | Half-hardy | — | Apr 23 – Apr 30 | Jun 22 – Jul 12 | Jun 24 – Jul 14 |
| Broccoli | Half-hardy | Mar 19 – Apr 2 | Apr 16 – Apr 30 | Jun 10 – Jun 30 | Jun 29 – Jul 19 |
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 USC00481547. 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 | May 26 | Jun 10 | Sep 17 | Sep 28 | 113 |
| 32°F (freeze) | May 14 | May 27 | Sep 26 | Oct 8 | 133 |
| 28°F | May 3 | May 16 | Oct 4 | Oct 18 | 152 |
| 24°F | Apr 24 | May 8 | Oct 14 | Oct 28 | 171 |
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) | 2,281 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 4,238 | cool-season crops (brassicas, greens) |
Hardiness zone 5b
Carpenter sits in USDA plant hardiness zone 5b on the 2023 map — meaning its average annual extreme minimum winter temperature is about −15 to −10 °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 5b, or see all USDA hardiness zones.
Frequently asked questions
- What USDA hardiness zone is Carpenter?
- Carpenter, Wyoming is in USDA plant hardiness zone 5b on the 2023 map (average annual extreme minimum temperature −15 to −10 °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 Carpenter?
- The average (median) last spring frost at 32°F is around May 14, 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 27, so wait until then before setting out frost-tender plants if you want to be safe.
- When is the first fall frost in Carpenter?
- The average first fall frost at 32°F is around September 26. That leaves a growing season of about 133 days between the average last spring and first fall frosts.
- When should I start tomatoes in Carpenter?
- Start tomato seeds indoors about Mar 19 – Apr 2 and transplant them outside about May 21 – May 28, once the danger of frost has passed. Estimated first harvest is around Jul 20 – Aug 9.
- How long is the growing season in Carpenter?
- About 133 days at the 32°F threshold (NOAA 1991–2020, median) — the span between the average last spring frost (~May 14) and the average first fall frost (~September 26). 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 USC00481547 (Carpenter 3n, 2.7 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.