Morongo Valley, CA 92256 planting calendar
- USDA zone
- 9b25 to 30 °F
- Last frost
- Feb 25avg, 32°F
- First frost
- Dec 15avg, 32°F
- Growing season
- 297days
Morongo Valley, California is in USDA plant hardiness zone 9b. Its average last spring frost is around February 25 and the first fall frost around December 15, giving a growing season of about 297 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.
Morongo Valley planting calendar
Each crop's windows are counted from Morongo Valley'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 14 | Mar 4 – Mar 11 | May 3 – May 23 | — |
| Pepper | Very tender | Jan 1 | Mar 11 – Mar 18 | May 10 – Jun 9 | — |
| Cucumber | Tender | Jan 28 – Feb 4 | Mar 4 – Mar 11 | Apr 23 – May 13 | — |
| Summer squash / zucchini | Tender | — | Mar 4 – Mar 11 | Apr 18 – May 3 | — |
| Bush bean | Tender | — | Mar 4 – Mar 11 | Apr 23 – May 3 | Oct 16 – Oct 26 |
| Sweet corn | Tender | — | Feb 25 – Mar 11 | Apr 26 – May 26 | — |
| Basil | Very tender | Jan 14 – Jan 28 | Mar 4 – Mar 11 | Apr 3 – Apr 18 | — |
| Lettuce | Half-hardy | Jan 14 – Jan 28 | Jan 28 – Feb 11 | Mar 14 – Mar 29 | Oct 2 – Oct 17 |
| Pea | Hardy | — | Jan 14 – Jan 28 | Mar 10 – Mar 25 | Sep 22 – Oct 7 |
| Spinach | Hardy | — | Jan 14 – Jan 28 | Feb 23 – Mar 5 | Oct 12 – Oct 22 |
| Carrot | Half-hardy | — | Feb 4 – Feb 11 | Apr 5 – Apr 25 | Sep 12 – Oct 2 |
| Broccoli | Half-hardy | Jan 1 – Jan 14 | Jan 28 – Feb 11 | Mar 24 – Apr 13 | Sep 17 – Oct 7 |
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 USC00045860. 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 31 | Apr 29 | Dec 1 | Dec 16 | 244 |
| 32°F (freeze) | Feb 25 | Apr 3 | Dec 15 | Jan 16 | 297 |
| 28°F | Jan 25 | Feb 28 | Jan 6 | Feb 14 | 352 |
| 24°F | Jan 14 | Jan 31 | Jan 13 | Jan 30 | 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) | 5,671 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 9,006 | cool-season crops (brassicas, greens) |
Hardiness zone 9b
Morongo Valley 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 Morongo Valley?
- Morongo Valley, 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 Morongo Valley?
- The average (median) last spring frost at 32°F is around February 25, from NOAA's 1991–2020 climate normals at the nearest reporting station. Roughly one year in ten the last frost is as late as April 3, so wait until then before setting out frost-tender plants if you want to be safe.
- When is the first fall frost in Morongo Valley?
- The average first fall frost at 32°F is around December 15. That leaves a growing season of about 297 days between the average last spring and first fall frosts.
- When should I start tomatoes in Morongo Valley?
- Start tomato seeds indoors about Jan 1 – Jan 14 and transplant them outside about Mar 4 – Mar 11, once the danger of frost has passed. Estimated first harvest is around May 3 – May 23.
- How long is the growing season in Morongo Valley?
- About 297 days at the 32°F threshold (NOAA 1991–2020, median) — the span between the average last spring frost (~February 25) and the average first fall frost (~December 15). 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 USC00045860 (Morongo Valley N, 5.4 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.