Frost Dates for Westminster, CO 80030
Westminster has 2 ZIP codes. The Westminster, CO frost page lists all of them with their dates.
Last spring frost May 4 · First fall frost October 2 · 151 frost-free days · USDA Zone 6a
ZIP 80030 has about 15,400 people, one of 2 ZIP codes in Westminster.
Moderate season: 151 frost-free days. Spring frost risk spans April 24–May 14 (20 days). Fall frost risk spans September 18–October 16 (28 days).
Frost probability for 80030
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 14 | May 4 | April 24 |
| Fall (first frost) | September 18 | October 2 | October 16 |
Dates come from NOAA 1971–2000 freeze probabilities at BOULDER (26.6 km away); the 50% date is the median year.
Which crops fit a 151-day season in Westminster
In Westminster (151 frost-free days, a moderate season), 34 of 56 planner crops fit outright, 21 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Mar 30 | May 18–May 25 | 109 | fits: 80 days to maturity, 109 available after May 18. | Jun 2 |
| Pepper | Mar 23 | May 18–May 25 | 109 | fits: 75 days to maturity, 109 available after May 18. | Jun 7 |
| Lettuce | Mar 9 | Apr 6–Apr 13 | 186 | two-plantings: Plant Apr 6 and again by Aug 11; both mature before Oct 9. | Aug 11 |
| Carrots | — | Apr 13–Apr 20 | 193 | fits: 70 days to maturity, 193 available after Apr 13. | Jul 31 |
| Cucumber | Apr 13 | May 18–May 25 | 123 | fits: 60 days to maturity, 123 available after May 18. | Jul 6 |
| Beans | — | May 11–May 25 | 137 | two-plantings: Plant May 11 and again by Jul 13; both mature before Sep 25. | Jul 13 |
| Peas | — | Mar 9–May 18 | 214 | fits: 65 days to maturity, 214 available after Mar 9. | Jul 22 |
| Zucchini | Apr 20 | May 18–May 25 | 123 | fits: 55 days to maturity, 123 available after May 18. | Jul 11 |
| Onion | Feb 9 | Apr 6–Apr 20 | 186 | fits: 100 days to maturity, 186 available after Apr 6. | — |
| Spinach | — | Mar 9–Apr 27 | 228 | two-plantings: Plant Mar 9 and again by Aug 30; both mature before Oct 23. | Aug 30 |
| Kale | Feb 23 | Apr 6–Apr 20 | 200 | two-plantings: Plant Apr 6 and again by Aug 15; both mature before Oct 23. | Aug 15 |
| Broccoli | Mar 9 | Apr 6–Apr 20 | 186 | fits: 80 days to maturity, 186 available after Apr 6. | Jul 7 |
| Cabbage | Mar 9 | Apr 6–Apr 20 | 200 | fits: 70 days to maturity, 200 available after Apr 6. | Jul 31 |
| Radish | — | Mar 9–Jun 1 | 214 | two-plantings: Plant Mar 9 and again by Aug 31; both mature before Oct 9. | Aug 31 |
| Beets | — | Mar 9–Jun 1 | 214 | two-plantings: Plant Mar 9 and again by Aug 1; both mature before Oct 9. | Aug 1 |
| Potatoes | — | Apr 20–Apr 27 | 172 | fits: 90 days to maturity, 172 available after Apr 20. | — |
| Garlic | — | Oct 2 | 256 | overwinter: Plant Oct 2 to Oct 23; harvest the following summer. | Oct 23 |
| Strawberry | — | Mar 30–May 25 | 207 | perennial: A perennial: plant Mar 30; it fruits from the following year and keeps producing for several years. | — |
| Corn | Apr 6 | May 11–May 18 | 123 | fits: 75 days to maturity, 123 available after May 11. | Jun 14 |
| Pumpkin | Apr 20 | May 18–May 18 | 116 | fits: 100 days to maturity, 116 available after May 18. | May 20 |
| Cauliflower | Mar 23 | Apr 27–May 11 | 165 | fits: 75 days to maturity, 165 available after Apr 27. | Jul 12 |
| Swiss Chard | Mar 9 | Apr 20–Apr 20 | 172 | two-plantings: Plant Apr 20 and again by Aug 1; both mature before Oct 9. | Aug 1 |
| Arugula | — | Mar 9–Jun 1 | 228 | two-plantings: Plant Mar 9 and again by Aug 30; both mature before Oct 23. | Aug 30 |
| Brussel Sprouts | Mar 9 | Apr 6–Apr 20 | 200 | fits: 100 days to maturity, 200 available after Apr 6. | Jul 1 |
| Butternut Squash | Apr 20 | May 18–May 25 | 116 | fits: 100 days to maturity, 116 available after May 18. | May 20 |
| Eggplant | Mar 16 | May 18–May 25 | 109 | fits: 70 days to maturity, 109 available after May 18. | Jun 12 |
| Okra | Apr 6 | May 11–May 18 | 130 | two-plantings: Plant May 11 and again by Jul 11; both mature before Sep 18. | Jul 11 |
| Basil | Mar 30 | May 25–May 25 | 116 | fits: 60 days to maturity, 116 available after May 25. | Jul 6 |
| Cilantro | — | Apr 6–Apr 27 | 186 | two-plantings: Plant Apr 6 and again by Aug 6; both mature before Oct 9. | Aug 6 |
| Parsley | Feb 23 | May 11–May 18 | 151 | fits: 70 days to maturity, 151 available after May 11. | Jul 17 |
| Celery | Feb 23 | May 11–May 25 | 151 | fits: 120 days to maturity, 151 available after May 11. | May 28 |
| Scallions | Feb 23 | Apr 6–Apr 20 | 200 | two-plantings: Plant Apr 6 and again by Aug 10; both mature before Oct 23. | Aug 10 |
| Turnip | — | Apr 6–Apr 20 | 200 | two-plantings: Plant Apr 6 and again by Aug 20; both mature before Oct 23. | Aug 20 |
| Kohlrabi | — | Mar 23–Apr 6 | 214 | two-plantings: Plant Mar 23 and again by Aug 15; both mature before Oct 23. | Aug 15 |
| Bok Choy | Apr 6 | Apr 27–May 4 | 165 | two-plantings: Plant Apr 27 and again by Aug 11; both mature before Oct 9. | Aug 11 |
| Collards | Feb 23 | Apr 6–Apr 20 | 200 | two-plantings: Plant Apr 6 and again by Aug 10; both mature before Oct 23. | Aug 10 |
| Cantaloupe | Apr 20 | May 18–May 25 | 109 | fits: 85 days to maturity, 109 available after May 18. | May 28 |
| Chives | Feb 9 | May 11–May 18 | 165 | fits: 90 days to maturity, 165 available after May 11. | — |
| Dill | — | Mar 9–Jun 1 | 214 | two-plantings: Plant Mar 9 and again by Aug 1; both mature before Oct 9. | Aug 1 |
| Oregano | Feb 23 | May 11–May 18 | 165 | fits: 80 days to maturity, 165 available after May 11. | — |
| Rosemary | Feb 9 | May 11–May 18 | 151 | fits: 80 days to maturity, 151 available after May 11. | — |
| Sage | Mar 9 | May 11–May 18 | 165 | fits: 75 days to maturity, 165 available after May 11. | — |
| Thyme | Feb 23 | May 11–May 18 | 165 | fits: 90 days to maturity, 165 available after May 11. | — |
| Calendula | Mar 23 | Apr 20–May 4 | 172 | two-plantings: Plant Apr 20 and again by Aug 6; both mature before Oct 9. | Aug 6 |
| Cosmos | Apr 6 | May 4–May 18 | 137 | two-plantings: Plant May 4 and again by Jul 6; both mature before Sep 18. | Jul 6 |
| Lavender | Feb 9 | May 4–May 18 | 172 | fits: 90 days to maturity, 172 available after May 4. | — |
| Marigolds | Mar 23 | May 4–May 11 | 137 | two-plantings: Plant May 4 and again by Jul 16; both mature before Sep 18. | Jul 16 |
| Melons | Apr 20 | May 18–May 25 | 109 | fits: 85 days to maturity, 109 available after May 18. | May 28 |
| Mint | — | May 4–May 18 | 172 | fits: 90 days to maturity, 172 available after May 4. | — |
| Nasturtiums | Apr 6 | May 4–May 11 | 137 | two-plantings: Plant May 4 and again by Jul 11; both mature before Sep 18. | Jul 11 |
| Pole Beans | — | May 11–May 25 | 130 | fits: 65 days to maturity, 130 available after May 11. | Jul 1 |
| Spaghetti Squash | Apr 20 | May 18–May 25 | 116 | fits: 90 days to maturity, 116 available after May 18. | May 30 |
| Sunflowers | — | May 4–May 18 | 137 | fits: 70 days to maturity, 137 available after May 4. | Jun 26 |
| Tomatillos | Mar 9 | May 11–May 18 | 116 | fits: 75 days to maturity, 116 available after May 11. | Jun 7 |
| Watermelon | Apr 20 | May 11–May 18 | 116 | fits: 80 days to maturity, 116 available after May 11. | Jun 2 |
| Yellow Squash | Apr 20 | May 18–May 25 | 123 | fits: 55 days to maturity, 123 available after May 18. | Jul 11 |
| Zinnias | Apr 6 | May 4–May 18 | 137 | two-plantings: Plant May 4 and again by Jul 6; both mature before Sep 18. | Jul 6 |
Month by month in Westminster
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 9), Lavender (Feb 9), Onion (Feb 9), Rosemary (Feb 9), Celery (Feb 23), Collards (Feb 23), +5 more. |
| March | Start indoors: Broccoli (Mar 9), Brussel Sprouts (Mar 9), Cabbage (Mar 9), Lettuce (Mar 9), Sage (Mar 9), Swiss Chard (Mar 9), +8 more. Direct sow from: Arugula (Mar 9), Beets (Mar 9), Dill (Mar 9), Peas (Mar 9), Radish (Mar 9), Spinach (Mar 9), +1 more. Plant: Strawberry (Mar 30). |
| April | Start indoors: Bok Choy (Apr 6), Corn (Apr 6), Cosmos (Apr 6), Nasturtiums (Apr 6), Okra (Apr 6), Zinnias (Apr 6), +9 more. Direct sow from: Cilantro (Apr 6), Turnip (Apr 6), Carrots (Apr 13), Potatoes (Apr 20). Transplant from: Broccoli (Apr 6), Brussel Sprouts (Apr 6), Cabbage (Apr 6), Collards (Apr 6), Kale (Apr 6), Lettuce (Apr 6), +6 more. |
| May | Direct sow from: Sunflowers (May 4), Beans (May 11), Pole Beans (May 11). Transplant from: Cosmos (May 4), Lavender (May 4), Marigolds (May 4), Mint (May 4), Nasturtiums (May 4), Zinnias (May 4), +23 more. Last frost around May 4. Last sowing dates: Butternut Squash (May 20), Pumpkin (May 20), Cantaloupe (May 28), Celery (May 28), Melons (May 28), Spaghetti Squash (May 30). |
| June | Last sowing dates: Tomato (Jun 2), Watermelon (Jun 2), Pepper (Jun 7), Tomatillos (Jun 7), Eggplant (Jun 12), Corn (Jun 14), +1 more. |
| July | Last sowing dates: Brussel Sprouts (Jul 1), Pole Beans (Jul 1), Basil (Jul 6), Cosmos (Jul 6), Cucumber (Jul 6), Zinnias (Jul 6), +12 more. |
| August | Last sowing dates: Beets (Aug 1), Dill (Aug 1), Swiss Chard (Aug 1), Calendula (Aug 6), Cilantro (Aug 6), Collards (Aug 10), +9 more. |
| September | First fall frost approaching (around October 2). Transplant fall brassicas. Sow spinach, arugula, and radishes. |
| October | Direct sow from: Garlic (Oct 2). First frost around October 2. Last sowing dates: Garlic (Oct 23). |
| November | Harvest remaining cold-hardy crops: kale, carrots, and beets. Plant garlic bulbs for next year. |
| December | Clean up spent plants. Add compost to beds. Rest, review, and plan next year's garden. |
Frequently Asked Questions
What is the last frost date for Westminster, CO (ZIP 80030)?
The median last spring frost date for Westminster, CO (ZIP code 80030) is around May 4. 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. One year in ten frost ends before April 24; one in ten it runs past May 14.
What is the first fall frost date in Westminster, CO?
The median first fall frost date for Westminster, CO is around October 2. 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 September 18 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Westminster, CO?
The frost-free growing season in Westminster is about 151 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 Westminster (151 frost-free days, a moderate season), 34 of 56 planner crops fit outright, 21 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Westminster, CO?
Westminster, CO is in USDA hardiness zone 6a (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 Westminster, CO?
Start tomatoes indoors Mar 30 and plant out May 18 in Westminster. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Westminster?
Two: plant Apr 6 and again by Aug 11; both mature before Oct 9.
When do I plant garlic in Westminster?
Oct 2 to Oct 23; it overwinters and is ready the following summer.
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