Monte Vista, CO planting calendar
- USDA zone
- 5a−20 to −15 °F
- Last frost
- Jun 11avg, 32°F
- First frost
- Sep 13avg, 32°F
- Growing season
- 92days
Monte Vista, Colorado is in USDA plant hardiness zone 5a. Its average last spring frost is around June 11 and the first fall frost around September 13, giving a growing season of about 92 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.
Monte Vista planting calendar
Each crop's windows are counted from Monte Vista'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 | Apr 16 – Apr 30 | Jun 18 – Jun 25 | Aug 17 – Sep 6 | — |
| Pepper | Very tender | Apr 2 – Apr 16 | Jun 25 – Jul 2 | Aug 24 – Sep 23 | — |
| Cucumber | Tender | May 14 – May 21 | Jun 18 – Jun 25 | Aug 7 – Aug 27 | — |
| Summer squash / zucchini | Tender | — | Jun 18 – Jun 25 | Aug 2 – Aug 17 | — |
| Bush bean | Tender | — | Jun 18 – Jun 25 | Aug 7 – Aug 17 | Jul 15 – Jul 25 |
| Sweet corn | Tender | — | Jun 11 – Jun 25 | Aug 10 – Sep 9 | — |
| Basil | Very tender | Apr 30 – May 14 | Jun 18 – Jun 25 | Jul 18 – Aug 2 | — |
| Lettuce | Half-hardy | Apr 30 – May 14 | May 14 – May 28 | Jun 28 – Jul 13 | Jul 1 – Jul 16 |
| Pea | Hardy | — | Apr 30 – May 14 | Jun 24 – Jul 9 | Jun 21 – Jul 6 |
| Spinach | Hardy | — | Apr 30 – May 14 | Jun 9 – Jun 19 | Jul 11 – Jul 21 |
| Carrot | Half-hardy | — | May 21 – May 28 | Jul 20 – Aug 9 | Jun 11 – Jul 1 |
| Broccoli | Half-hardy | Apr 16 – Apr 30 | May 14 – May 28 | Jul 8 – Jul 28 | Jun 16 – Jul 6 |
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 USC00055706. 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 | — | — | — | — | 62 |
| 32°F (freeze) | Jun 11 | Jun 25 | Sep 13 | Sep 24 | 92 |
| 28°F | May 30 | Jun 12 | Sep 23 | Oct 4 | 115 |
| 24°F | May 15 | May 29 | Sep 30 | Oct 12 | 139 |
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) | 1,170 | standard warm-season base (tomato, corn, beans) |
| Base 40°F (cool-season) | 2,832 | cool-season crops (brassicas, greens) |
Hardiness zone 5a
Monte Vista sits in USDA plant hardiness zone 5a on the 2023 map — meaning its average annual extreme minimum winter temperature is about −20 to −15 °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 5a, or see all USDA hardiness zones.
Frequently asked questions
- What USDA hardiness zone is Monte Vista?
- Monte Vista, Colorado is in USDA plant hardiness zone 5a on the 2023 map (average annual extreme minimum temperature −20 to −15 °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 Monte Vista?
- The average (median) last spring frost at 32°F is around June 11, from NOAA's 1991–2020 climate normals at the nearest reporting station. Roughly one year in ten the last frost is as late as June 25, so wait until then before setting out frost-tender plants if you want to be safe.
- When is the first fall frost in Monte Vista?
- The average first fall frost at 32°F is around September 13. That leaves a growing season of about 92 days between the average last spring and first fall frosts.
- When should I start tomatoes in Monte Vista?
- Start tomato seeds indoors about Apr 16 – Apr 30 and transplant them outside about Jun 18 – Jun 25, once the danger of frost has passed. Estimated first harvest is around Aug 17 – Sep 6.
- How long is the growing season in Monte Vista?
- About 92 days at the 32°F threshold (NOAA 1991–2020, median) — the span between the average last spring frost (~June 11) and the average first fall frost (~September 13). 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 USC00055706 (Monte Vista 2w, 5.2 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.