Frost Dates for Alhambra, CA 91801
Last spring frost January 11 · First fall frost January 5 · 359 frost-free days · USDA Zone 10a
ZIP 91801 has about 53,400 people, the largest of 2 ZIP codes in Alhambra.
Very long season: 359 frost-free days.
Frost probability for 91801
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | February 20 | January 11 | — |
| Fall (first frost) | December 1 | January 5 | — |
Dates come from NOAA 1971–2000 freeze probabilities at SAN GABRIEL FIRE DEPT (2.6 km away); the 50% date is the median year.
Frost dates by ZIP code in Alhambra, CA
| ZIP | Last spring frost (50%) | First fall frost (50%) | Zone |
|---|---|---|---|
| 91801 | January 11 | January 5 | 10a |
| 91803 | — | — | 10b |
Which crops fit a 359-day season in Alhambra
In Alhambra (359 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 7 | Jan 25–Feb 1 | 317 | fits: 80 days to maturity, 317 available after Jan 25. | Sep 5 |
| Pepper | Nov 30 | Jan 25–Feb 1 | 317 | fits: 75 days to maturity, 317 available after Jan 25. | Sep 10 |
| Lettuce | Nov 16 | Dec 14–Dec 21 | 394 | two-plantings: Plant Dec 14 and again by Nov 14; both mature before Jan 12. | Nov 14 |
| Carrots | — | Dec 21–Dec 28 | 401 | fits: 70 days to maturity, 401 available after Dec 21. | Nov 3 |
| Cucumber | Dec 21 | Jan 25–Feb 1 | 331 | two-plantings: Plant Jan 25 and again by Oct 9; both mature before Dec 22. | Oct 9 |
| Beans | — | Jan 18–Feb 1 | 345 | two-plantings: Plant Jan 18 and again by Oct 16; both mature before Dec 29. | Oct 16 |
| Peas | — | Nov 16–Jan 25 | 422 | fits: 65 days to maturity, 422 available after Nov 16. | Oct 25 |
| Zucchini | Dec 28 | Jan 25–Feb 1 | 331 | two-plantings: Plant Jan 25 and again by Oct 14; both mature before Dec 22. | Oct 14 |
| Onion | Oct 19 | Dec 14–Dec 28 | 394 | fits: 100 days to maturity, 394 available after Dec 14. | — |
| Spinach | — | Nov 16–Jan 4 | 436 | two-plantings: Plant Nov 16 and again by Dec 3; both mature before Jan 26. | Dec 3 |
| Kale | Nov 2 | Dec 14–Dec 28 | 408 | two-plantings: Plant Dec 14 and again by Nov 18; both mature before Jan 26. | Nov 18 |
| Broccoli | Nov 16 | Dec 14–Dec 28 | 394 | fits: 80 days to maturity, 394 available after Dec 14. | Oct 10 |
| Cabbage | Nov 16 | Dec 14–Dec 28 | 408 | fits: 70 days to maturity, 408 available after Dec 14. | Nov 3 |
| Radish | — | Nov 16–Feb 8 | 422 | two-plantings: Plant Nov 16 and again by Dec 4; both mature before Jan 12. | Dec 4 |
| Beets | — | Nov 16–Feb 8 | 422 | two-plantings: Plant Nov 16 and again by Nov 4; both mature before Jan 12. | Nov 4 |
| Potatoes | — | Dec 28–Jan 4 | 380 | fits: 90 days to maturity, 380 available after Dec 28. | — |
| Garlic | — | Jan 5 | 464 | overwinter: Plant Jan 5 to Jan 26; harvest the following summer. | Jan 26 |
| Strawberry | — | Dec 7–Feb 1 | 415 | perennial: A perennial: plant Dec 7; it fruits from the following year and keeps producing for several years. | — |
| Corn | Dec 14 | Jan 18–Jan 25 | 331 | fits: 75 days to maturity, 331 available after Jan 18. | Sep 17 |
| Pumpkin | Dec 28 | Jan 25–Jan 25 | 324 | fits: 100 days to maturity, 324 available after Jan 25. | Aug 23 |
| Cauliflower | Nov 30 | Jan 4–Jan 18 | 373 | fits: 75 days to maturity, 373 available after Jan 4. | Oct 15 |
| Swiss Chard | Nov 16 | Dec 28–Dec 28 | 380 | two-plantings: Plant Dec 28 and again by Nov 4; both mature before Jan 12. | Nov 4 |
| Arugula | — | Nov 16–Feb 8 | 436 | two-plantings: Plant Nov 16 and again by Dec 3; both mature before Jan 26. | Dec 3 |
| Brussel Sprouts | Nov 16 | Dec 14–Dec 28 | 408 | fits: 100 days to maturity, 408 available after Dec 14. | Oct 4 |
| Butternut Squash | Dec 28 | Jan 25–Feb 1 | 324 | fits: 100 days to maturity, 324 available after Jan 25. | Aug 23 |
| Eggplant | Nov 23 | Jan 25–Feb 1 | 317 | fits: 70 days to maturity, 317 available after Jan 25. | Sep 15 |
| Okra | Dec 14 | Jan 18–Jan 25 | 338 | two-plantings: Plant Jan 18 and again by Oct 14; both mature before Dec 22. | Oct 14 |
| Basil | Dec 7 | Feb 1–Feb 1 | 324 | two-plantings: Plant Feb 1 and again by Oct 9; both mature before Dec 22. | Oct 9 |
| Cilantro | — | Dec 14–Jan 4 | 394 | two-plantings: Plant Dec 14 and again by Nov 9; both mature before Jan 12. | Nov 9 |
| Parsley | Nov 2 | Jan 18–Jan 25 | 359 | fits: 70 days to maturity, 359 available after Jan 18. | Oct 20 |
| Celery | Nov 2 | Jan 18–Feb 1 | 359 | fits: 120 days to maturity, 359 available after Jan 18. | Aug 31 |
| Scallions | Nov 2 | Dec 14–Dec 28 | 408 | two-plantings: Plant Dec 14 and again by Nov 13; both mature before Jan 26. | Nov 13 |
| Turnip | — | Dec 14–Dec 28 | 408 | two-plantings: Plant Dec 14 and again by Nov 23; both mature before Jan 26. | Nov 23 |
| Kohlrabi | — | Nov 30–Dec 14 | 422 | two-plantings: Plant Nov 30 and again by Nov 18; both mature before Jan 26. | Nov 18 |
| Bok Choy | Dec 14 | Jan 4–Jan 11 | 373 | two-plantings: Plant Jan 4 and again by Nov 14; both mature before Jan 12. | Nov 14 |
| Collards | Nov 2 | Dec 14–Dec 28 | 408 | two-plantings: Plant Dec 14 and again by Nov 13; both mature before Jan 26. | Nov 13 |
| Cantaloupe | Dec 28 | Jan 25–Feb 1 | 317 | fits: 85 days to maturity, 317 available after Jan 25. | Aug 31 |
| Chives | Oct 19 | Jan 18–Jan 25 | 373 | fits: 90 days to maturity, 373 available after Jan 18. | — |
| Dill | — | Nov 16–Feb 8 | 422 | two-plantings: Plant Nov 16 and again by Nov 4; both mature before Jan 12. | Nov 4 |
| Oregano | Nov 2 | Jan 18–Jan 25 | 373 | fits: 80 days to maturity, 373 available after Jan 18. | — |
| Rosemary | Oct 19 | Jan 18–Jan 25 | 359 | fits: 80 days to maturity, 359 available after Jan 18. | — |
| Sage | Nov 16 | Jan 18–Jan 25 | 373 | fits: 75 days to maturity, 373 available after Jan 18. | — |
| Thyme | Nov 2 | Jan 18–Jan 25 | 373 | fits: 90 days to maturity, 373 available after Jan 18. | — |
| Calendula | Nov 30 | Dec 28–Jan 11 | 380 | two-plantings: Plant Dec 28 and again by Nov 9; both mature before Jan 12. | Nov 9 |
| Cosmos | Dec 14 | Jan 11–Jan 25 | 345 | two-plantings: Plant Jan 11 and again by Oct 9; both mature before Dec 22. | Oct 9 |
| Lavender | Oct 19 | Jan 11–Jan 25 | 380 | fits: 90 days to maturity, 380 available after Jan 11. | — |
| Marigolds | Nov 30 | Jan 11–Jan 18 | 345 | two-plantings: Plant Jan 11 and again by Oct 19; both mature before Dec 22. | Oct 19 |
| Melons | Dec 28 | Jan 25–Feb 1 | 317 | fits: 85 days to maturity, 317 available after Jan 25. | Aug 31 |
| Mint | — | Jan 11–Jan 25 | 380 | fits: 90 days to maturity, 380 available after Jan 11. | — |
| Nasturtiums | Dec 14 | Jan 11–Jan 18 | 345 | two-plantings: Plant Jan 11 and again by Oct 14; both mature before Dec 22. | Oct 14 |
| Pole Beans | — | Jan 18–Feb 1 | 338 | fits: 65 days to maturity, 338 available after Jan 18. | Oct 4 |
| Spaghetti Squash | Dec 28 | Jan 25–Feb 1 | 324 | fits: 90 days to maturity, 324 available after Jan 25. | Sep 2 |
| Sunflowers | — | Jan 11–Jan 25 | 345 | fits: 70 days to maturity, 345 available after Jan 11. | Sep 29 |
| Tomatillos | Nov 16 | Jan 18–Jan 25 | 324 | fits: 75 days to maturity, 324 available after Jan 18. | Sep 10 |
| Watermelon | Dec 28 | Jan 18–Jan 25 | 324 | fits: 80 days to maturity, 324 available after Jan 18. | Sep 5 |
| Yellow Squash | Dec 28 | Jan 25–Feb 1 | 331 | two-plantings: Plant Jan 25 and again by Oct 14; both mature before Dec 22. | Oct 14 |
| Zinnias | Dec 14 | Jan 11–Jan 25 | 345 | two-plantings: Plant Jan 11 and again by Oct 9; both mature before Dec 22. | Oct 9 |
Month by month in Alhambra
| Month | What to do |
|---|---|
| January | Direct sow from: Garlic (Jan 5), Sunflowers (Jan 11), Beans (Jan 18), Pole Beans (Jan 18). Transplant from: Bok Choy (Jan 4), Cauliflower (Jan 4), Cosmos (Jan 11), Lavender (Jan 11), Marigolds (Jan 11), Mint (Jan 11), +24 more. Last frost around January 11. First frost around January 5. Last sowing dates: Garlic (Jan 26). |
| February | Transplant from: Basil (Feb 1). |
| March | Transplant warm-season crops outdoors. Sow beans, cucumbers, and squash. |
| April | Main warm-season planting window. Direct sow melons and sweet corn. |
| May | Succession plant lettuce. Keep beds irrigated as temperatures climb. |
| June | Monitor for heat stress. Harvest zucchini and cucumbers frequently. |
| July | Harvest regularly to encourage continued production. Watch for pests. |
| August | Last sowing dates: Butternut Squash (Aug 23), Pumpkin (Aug 23), Cantaloupe (Aug 31), Celery (Aug 31), Melons (Aug 31). |
| September | Last sowing dates: Spaghetti Squash (Sep 2), Tomato (Sep 5), Watermelon (Sep 5), Pepper (Sep 10), Tomatillos (Sep 10), Eggplant (Sep 15), +2 more. |
| October | Start indoors: Chives (Oct 19), Lavender (Oct 19), Onion (Oct 19), Rosemary (Oct 19). Last sowing dates: Brussel Sprouts (Oct 4), Pole Beans (Oct 4), Basil (Oct 9), Cosmos (Oct 9), Cucumber (Oct 9), Zinnias (Oct 9), +10 more. |
| November | Start indoors: Celery (Nov 2), Collards (Nov 2), Kale (Nov 2), Oregano (Nov 2), Parsley (Nov 2), Scallions (Nov 2), +13 more. Direct sow from: Arugula (Nov 16), Beets (Nov 16), Dill (Nov 16), Peas (Nov 16), Radish (Nov 16), Spinach (Nov 16), +1 more. Last sowing dates: Cabbage (Nov 3), Carrots (Nov 3), Beets (Nov 4), Dill (Nov 4), Swiss Chard (Nov 4), Calendula (Nov 9), +8 more. |
| December | Start indoors: Basil (Dec 7), Tomato (Dec 7), Bok Choy (Dec 14), Corn (Dec 14), Cosmos (Dec 14), Nasturtiums (Dec 14), +11 more. Direct sow from: Cilantro (Dec 14), Turnip (Dec 14), Carrots (Dec 21), Potatoes (Dec 28). Transplant from: Broccoli (Dec 14), Brussel Sprouts (Dec 14), Cabbage (Dec 14), Collards (Dec 14), Kale (Dec 14), Lettuce (Dec 14), +4 more. Plant: Strawberry (Dec 7). Last sowing dates: Arugula (Dec 3), Spinach (Dec 3), Radish (Dec 4). |
Frequently Asked Questions
What is the last frost date for Alhambra, CA (ZIP 91801)?
The median last spring frost date for Alhambra, CA (ZIP code 91801) is around January 11. 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 Alhambra, CA?
The median first fall frost date for Alhambra, CA is around January 5. 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 December 1 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Alhambra, CA?
The frost-free growing season in Alhambra is about 359 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 Alhambra (359 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 Alhambra, CA?
Alhambra, 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 Alhambra, CA?
Start tomatoes indoors Dec 7 and plant out Jan 25 in Alhambra. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Alhambra?
Two: plant Dec 14 and again by Nov 14; both mature before Jan 12.
When do I plant garlic in Alhambra?
Jan 5 to Jan 26; it overwinters and is ready the following summer.
Can I get two tomato crops in Alhambra?
Yes: plant out Jan 25 for a summer crop, and set out a second round of transplants by Sep 5 for a fall crop.
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