Elmira, CA planting calendar
- USDA zone
- 9b25 to 30 °F
- Last frost
- Feb 18avg, 32°F
- First frost
- Nov 28avg, 32°F
- Growing season
- 283days
Elmira, California is in USDA plant hardiness zone 9b. Its average last spring frost is around February 18 and the first fall frost around November 28, giving a growing season of about 283 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.
Elmira planting calendar
Each crop's windows are counted from Elmira'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 | Jan 1 – Jan 7 | Feb 25 – Mar 4 | Apr 26 – May 16 | — |
| Pepper | Very tender | Jan 1 | Mar 4 – Mar 11 | May 3 – Jun 2 | — |
| Cucumber | Tender | Jan 21 – Jan 28 | Feb 25 – Mar 4 | Apr 16 – May 6 | — |
| Summer squash / zucchini | Tender | — | Feb 25 – Mar 4 | Apr 11 – Apr 26 | — |
| Bush bean | Tender | — | Feb 25 – Mar 4 | Apr 16 – Apr 26 | Sep 29 – Oct 9 |
| Sweet corn | Tender | — | Feb 18 – Mar 4 | Apr 19 – May 19 | — |
| Basil | Very tender | Jan 7 – Jan 21 | Feb 25 – Mar 4 | Mar 27 – Apr 11 | — |
| Lettuce | Half-hardy | Jan 7 – Jan 21 | Jan 21 – Feb 4 | Mar 7 – Mar 22 | Sep 15 – Sep 30 |
| Pea | Hardy | — | Jan 7 – Jan 21 | Mar 3 – Mar 18 | Sep 5 – Sep 20 |
| Spinach | Hardy | — | Jan 7 – Jan 21 | Feb 16 – Feb 26 | Sep 25 – Oct 5 |
| Carrot | Half-hardy | — | Jan 28 – Feb 4 | Mar 29 – Apr 18 | Aug 26 – Sep 15 |
| Broccoli | Half-hardy | Jan 1 – Jan 7 | Jan 21 – Feb 4 | Mar 17 – Apr 6 | Aug 31 – Sep 20 |
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 USW00093241. 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 | Mar 28 | Apr 19 | Nov 13 | Nov 30 | 230 |
| 32°F (freeze) | Feb 18 | Mar 25 | Nov 28 | Dec 18 | 283 |
| 28°F | Jan 15 | Feb 17 | Dec 10 | Jan 11 | 334 |
| 24°F | Dec 31 | Jan 29 | Dec 21 | Jan 17 | 365 |
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) | 4,707 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 8,080 | cool-season crops (brassicas, greens) |
Hardiness zone 9b
Elmira sits in USDA plant hardiness zone 9b on the 2023 map — meaning its average annual extreme minimum winter temperature is about 25 to 30 °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 9b, or see all USDA hardiness zones.
Frequently asked questions
- What USDA hardiness zone is Elmira?
- Elmira, California is in USDA plant hardiness zone 9b on the 2023 map (average annual extreme minimum temperature 25 to 30 °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 Elmira?
- The average (median) last spring frost at 32°F is around February 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 March 25, so wait until then before setting out frost-tender plants if you want to be safe.
- When is the first fall frost in Elmira?
- The average first fall frost at 32°F is around November 28. That leaves a growing season of about 283 days between the average last spring and first fall frosts.
- When should I start tomatoes in Elmira?
- Start tomato seeds indoors about Jan 1 – Jan 7 and transplant them outside about Feb 25 – Mar 4, once the danger of frost has passed. Estimated first harvest is around Apr 26 – May 16.
- How long is the growing season in Elmira?
- About 283 days at the 32°F threshold (NOAA 1991–2020, median) — the span between the average last spring frost (~February 18) and the average first fall frost (~November 28). 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 USW00093241 (Vacaville Nut Tree Ap, 4.8 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.