Frost Dates for Rancho Cucamonga, CA 91739
Rancho Cucamonga has 4 ZIP codes. The Rancho Cucamonga, CA frost page lists all of them with their dates.
Last spring frost January 19 · First fall frost December 23 · 338 frost-free days · USDA Zone 10a
ZIP 91739 has about 41,700 people, one of 4 ZIP codes in Rancho Cucamonga.
Very long season: 338 frost-free days.
Frost probability for 91739
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | March 5 | January 19 | — |
| Fall (first frost) | November 21 | December 23 | — |
Dates come from NOAA 1971–2000 freeze probabilities at POMONA/FAIRPLEX (24.7 km away); the 50% date is the median year.
Which crops fit a 338-day season in Rancho Cucamonga
In Rancho Cucamonga (338 frost-free days, a very long season), 30 of 56 planner crops fit outright, 25 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Dec 15 | Feb 2–Feb 9 | 296 | fits: 80 days to maturity, 296 available after Feb 2. | Aug 23 |
| Pepper | Dec 8 | Feb 2–Feb 9 | 296 | fits: 75 days to maturity, 296 available after Feb 2. | Aug 28 |
| Lettuce | Nov 24 | Dec 22–Dec 29 | 373 | two-plantings: Plant Dec 22 and again by Nov 1; both mature before Dec 30. | Nov 1 |
| Carrots | — | Dec 29–Jan 5 | 380 | fits: 70 days to maturity, 380 available after Dec 29. | Oct 21 |
| Cucumber | Dec 29 | Feb 2–Feb 9 | 310 | two-plantings: Plant Feb 2 and again by Sep 26; both mature before Dec 9. | Sep 26 |
| Beans | — | Jan 26–Feb 9 | 324 | two-plantings: Plant Jan 26 and again by Oct 3; both mature before Dec 16. | Oct 3 |
| Peas | — | Nov 24–Feb 2 | 401 | fits: 65 days to maturity, 401 available after Nov 24. | Oct 12 |
| Zucchini | Jan 5 | Feb 2–Feb 9 | 310 | two-plantings: Plant Feb 2 and again by Oct 1; both mature before Dec 9. | Oct 1 |
| Onion | Oct 27 | Dec 22–Jan 5 | 373 | fits: 100 days to maturity, 373 available after Dec 22. | — |
| Spinach | — | Nov 24–Jan 12 | 415 | two-plantings: Plant Nov 24 and again by Nov 20; both mature before Jan 13. | Nov 20 |
| Kale | Nov 10 | Dec 22–Jan 5 | 387 | two-plantings: Plant Dec 22 and again by Nov 5; both mature before Jan 13. | Nov 5 |
| Broccoli | Nov 24 | Dec 22–Jan 5 | 373 | fits: 80 days to maturity, 373 available after Dec 22. | Sep 27 |
| Cabbage | Nov 24 | Dec 22–Jan 5 | 387 | fits: 70 days to maturity, 387 available after Dec 22. | Oct 21 |
| Radish | — | Nov 24–Feb 16 | 401 | two-plantings: Plant Nov 24 and again by Nov 21; both mature before Dec 30. | Nov 21 |
| Beets | — | Nov 24–Feb 16 | 401 | two-plantings: Plant Nov 24 and again by Oct 22; both mature before Dec 30. | Oct 22 |
| Potatoes | — | Jan 5–Jan 12 | 359 | fits: 90 days to maturity, 359 available after Jan 5. | — |
| Garlic | — | Dec 23 | 443 | overwinter: Plant Dec 23 to Jan 13; harvest the following summer. | Jan 13 |
| Strawberry | — | Dec 15–Feb 9 | 394 | perennial: A perennial: plant Dec 15; it fruits from the following year and keeps producing for several years. | — |
| Corn | Dec 22 | Jan 26–Feb 2 | 310 | fits: 75 days to maturity, 310 available after Jan 26. | Sep 4 |
| Pumpkin | Jan 5 | Feb 2–Feb 2 | 303 | fits: 100 days to maturity, 303 available after Feb 2. | Aug 10 |
| Cauliflower | Dec 8 | Jan 12–Jan 26 | 352 | fits: 75 days to maturity, 352 available after Jan 12. | Oct 2 |
| Swiss Chard | Nov 24 | Jan 5–Jan 5 | 359 | two-plantings: Plant Jan 5 and again by Oct 22; both mature before Dec 30. | Oct 22 |
| Arugula | — | Nov 24–Feb 16 | 415 | two-plantings: Plant Nov 24 and again by Nov 20; both mature before Jan 13. | Nov 20 |
| Brussel Sprouts | Nov 24 | Dec 22–Jan 5 | 387 | fits: 100 days to maturity, 387 available after Dec 22. | Sep 21 |
| Butternut Squash | Jan 5 | Feb 2–Feb 9 | 303 | fits: 100 days to maturity, 303 available after Feb 2. | Aug 10 |
| Eggplant | Dec 1 | Feb 2–Feb 9 | 296 | fits: 70 days to maturity, 296 available after Feb 2. | Sep 2 |
| Okra | Dec 22 | Jan 26–Feb 2 | 317 | two-plantings: Plant Jan 26 and again by Oct 1; both mature before Dec 9. | Oct 1 |
| Basil | Dec 15 | Feb 9–Feb 9 | 303 | two-plantings: Plant Feb 9 and again by Sep 26; both mature before Dec 9. | Sep 26 |
| Cilantro | — | Dec 22–Jan 12 | 373 | two-plantings: Plant Dec 22 and again by Oct 27; both mature before Dec 30. | Oct 27 |
| Parsley | Nov 10 | Jan 26–Feb 2 | 338 | fits: 70 days to maturity, 338 available after Jan 26. | Oct 7 |
| Celery | Nov 10 | Jan 26–Feb 9 | 338 | fits: 120 days to maturity, 338 available after Jan 26. | Aug 18 |
| Scallions | Nov 10 | Dec 22–Jan 5 | 387 | two-plantings: Plant Dec 22 and again by Oct 31; both mature before Jan 13. | Oct 31 |
| Turnip | — | Dec 22–Jan 5 | 387 | two-plantings: Plant Dec 22 and again by Nov 10; both mature before Jan 13. | Nov 10 |
| Kohlrabi | — | Dec 8–Dec 22 | 401 | two-plantings: Plant Dec 8 and again by Nov 5; both mature before Jan 13. | Nov 5 |
| Bok Choy | Dec 22 | Jan 12–Jan 19 | 352 | two-plantings: Plant Jan 12 and again by Nov 1; both mature before Dec 30. | Nov 1 |
| Collards | Nov 10 | Dec 22–Jan 5 | 387 | two-plantings: Plant Dec 22 and again by Oct 31; both mature before Jan 13. | Oct 31 |
| Cantaloupe | Jan 5 | Feb 2–Feb 9 | 296 | fits: 85 days to maturity, 296 available after Feb 2. | Aug 18 |
| Chives | Oct 27 | Jan 26–Feb 2 | 352 | fits: 90 days to maturity, 352 available after Jan 26. | — |
| Dill | — | Nov 24–Feb 16 | 401 | two-plantings: Plant Nov 24 and again by Oct 22; both mature before Dec 30. | Oct 22 |
| Oregano | Nov 10 | Jan 26–Feb 2 | 352 | fits: 80 days to maturity, 352 available after Jan 26. | — |
| Rosemary | Oct 27 | Jan 26–Feb 2 | 338 | fits: 80 days to maturity, 338 available after Jan 26. | — |
| Sage | Nov 24 | Jan 26–Feb 2 | 352 | fits: 75 days to maturity, 352 available after Jan 26. | — |
| Thyme | Nov 10 | Jan 26–Feb 2 | 352 | fits: 90 days to maturity, 352 available after Jan 26. | — |
| Calendula | Dec 8 | Jan 5–Jan 19 | 359 | two-plantings: Plant Jan 5 and again by Oct 27; both mature before Dec 30. | Oct 27 |
| Cosmos | Dec 22 | Jan 19–Feb 2 | 324 | two-plantings: Plant Jan 19 and again by Sep 26; both mature before Dec 9. | Sep 26 |
| Lavender | Oct 27 | Jan 19–Feb 2 | 359 | fits: 90 days to maturity, 359 available after Jan 19. | — |
| Marigolds | Dec 8 | Jan 19–Jan 26 | 324 | two-plantings: Plant Jan 19 and again by Oct 6; both mature before Dec 9. | Oct 6 |
| Melons | Jan 5 | Feb 2–Feb 9 | 296 | fits: 85 days to maturity, 296 available after Feb 2. | Aug 18 |
| Mint | — | Jan 19–Feb 2 | 359 | fits: 90 days to maturity, 359 available after Jan 19. | — |
| Nasturtiums | Dec 22 | Jan 19–Jan 26 | 324 | two-plantings: Plant Jan 19 and again by Oct 1; both mature before Dec 9. | Oct 1 |
| Pole Beans | — | Jan 26–Feb 9 | 317 | fits: 65 days to maturity, 317 available after Jan 26. | Sep 21 |
| Spaghetti Squash | Jan 5 | Feb 2–Feb 9 | 303 | fits: 90 days to maturity, 303 available after Feb 2. | Aug 20 |
| Sunflowers | — | Jan 19–Feb 2 | 324 | fits: 70 days to maturity, 324 available after Jan 19. | Sep 16 |
| Tomatillos | Nov 24 | Jan 26–Feb 2 | 303 | fits: 75 days to maturity, 303 available after Jan 26. | Aug 28 |
| Watermelon | Jan 5 | Jan 26–Feb 2 | 303 | fits: 80 days to maturity, 303 available after Jan 26. | Aug 23 |
| Yellow Squash | Jan 5 | Feb 2–Feb 9 | 310 | two-plantings: Plant Feb 2 and again by Oct 1; both mature before Dec 9. | Oct 1 |
| Zinnias | Dec 22 | Jan 19–Feb 2 | 324 | two-plantings: Plant Jan 19 and again by Sep 26; both mature before Dec 9. | Sep 26 |
Month by month in Rancho Cucamonga
| Month | What to do |
|---|---|
| January | Start indoors: Butternut Squash (Jan 5), Cantaloupe (Jan 5), Melons (Jan 5), Pumpkin (Jan 5), Spaghetti Squash (Jan 5), Watermelon (Jan 5), +2 more. Direct sow from: Potatoes (Jan 5), Sunflowers (Jan 19), Beans (Jan 26), Pole Beans (Jan 26). Transplant from: Calendula (Jan 5), Swiss Chard (Jan 5), Bok Choy (Jan 12), Cauliflower (Jan 12), Cosmos (Jan 19), Lavender (Jan 19), +15 more. Last frost around January 19. Last sowing dates: Garlic (Jan 13). |
| February | Transplant from: Butternut Squash (Feb 2), Cantaloupe (Feb 2), Cucumber (Feb 2), Eggplant (Feb 2), Melons (Feb 2), Pepper (Feb 2), +6 more. |
| March | Succession plant lettuce and greens. Keep beds weeded and watered consistently. |
| April | Harvest regularly to encourage production. Monitor for pests and disease. |
| May | Midsummer: harvest beans, zucchini, cucumbers. Start brassica seeds indoors for fall. |
| June | Direct sow carrots and beets for fall harvest. Start fall broccoli and kale indoors. |
| July | Direct sow carrots and beets for fall harvest. Start fall broccoli and kale indoors. |
| August | Last sowing dates: Butternut Squash (Aug 10), Pumpkin (Aug 10), Cantaloupe (Aug 18), Celery (Aug 18), Melons (Aug 18), Spaghetti Squash (Aug 20), +4 more. |
| September | Last sowing dates: Eggplant (Sep 2), Corn (Sep 4), Sunflowers (Sep 16), Brussel Sprouts (Sep 21), Pole Beans (Sep 21), Basil (Sep 26), +4 more. |
| October | Start indoors: Chives (Oct 27), Lavender (Oct 27), Onion (Oct 27), Rosemary (Oct 27). Last sowing dates: Nasturtiums (Oct 1), Okra (Oct 1), Yellow Squash (Oct 1), Zucchini (Oct 1), Cauliflower (Oct 2), Beans (Oct 3), +12 more. |
| November | Start indoors: Celery (Nov 10), Collards (Nov 10), Kale (Nov 10), Oregano (Nov 10), Parsley (Nov 10), Scallions (Nov 10), +8 more. Direct sow from: Arugula (Nov 24), Beets (Nov 24), Dill (Nov 24), Peas (Nov 24), Radish (Nov 24), Spinach (Nov 24). Last sowing dates: Bok Choy (Nov 1), Lettuce (Nov 1), Kale (Nov 5), Kohlrabi (Nov 5), Turnip (Nov 10), Arugula (Nov 20), +2 more. |
| December | Start indoors: Eggplant (Dec 1), Calendula (Dec 8), Cauliflower (Dec 8), Marigolds (Dec 8), Pepper (Dec 8), Basil (Dec 15), +8 more. Direct sow from: Kohlrabi (Dec 8), Cilantro (Dec 22), Turnip (Dec 22), Garlic (Dec 23), Carrots (Dec 29). Transplant from: Broccoli (Dec 22), Brussel Sprouts (Dec 22), Cabbage (Dec 22), Collards (Dec 22), Kale (Dec 22), Lettuce (Dec 22), +2 more. Plant: Strawberry (Dec 15). First frost around December 23. |
Frequently Asked Questions
What is the last frost date for Rancho Cucamonga, CA (ZIP 91739)?
The median last spring frost date for Rancho Cucamonga, CA (ZIP code 91739) is around January 19. This is the 50th-percentile date — meaning half of all years see frost end before this date. Use the 10% and 90% dates to understand the full range of risk in your area.
What is the first fall frost date in Rancho Cucamonga, CA?
The median first fall frost date for Rancho Cucamonga, CA is around December 23. Plan to harvest or protect frost-sensitive crops like tomatoes and peppers at least a week before this date to avoid losses. The first frost arrives around November 21 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Rancho Cucamonga, CA?
The frost-free growing season in Rancho Cucamonga is about 338 days. This window — from your last spring frost to your first fall frost — is when warm-season vegetables thrive. Cold-hardy crops like kale, spinach, and peas can extend your season by weeks on either side. In Rancho Cucamonga (338 frost-free days, a very long season), 30 of 56 planner crops fit outright, 25 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Rancho Cucamonga, CA?
Rancho Cucamonga, CA is in USDA hardiness zone 10a (2023 USDA Plant Hardiness Zone Map). Zones come from the average coldest winter temperature, so they tell you which perennials survive the winter; the frost dates on this page tell you when to plant.
When should I start tomatoes indoors in Rancho Cucamonga, CA?
Start tomatoes indoors Dec 15 and plant out Feb 2 in Rancho Cucamonga. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Rancho Cucamonga?
Two: plant Dec 22 and again by Nov 1; both mature before Dec 30.
When do I plant garlic in Rancho Cucamonga?
Dec 23 to Jan 13; it overwinters and is ready the following summer.
Can I get two tomato crops in Rancho Cucamonga?
Yes: plant out Feb 2 for a summer crop, and set out a second round of transplants by Aug 23 for a fall crop.
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