Frost Dates for Silverthorne, CO 80498
Last spring frost June 23 · First fall frost September 2 · 71 frost-free days · USDA Zone 5a
ZIP 80498 has about 8,880 people.
Short season: 71 frost-free days. Spring frost risk spans June 6–July 13 (37 days). Fall frost risk spans August 14–September 20 (37 days).
Frost probability for 80498
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | July 13 | June 23 | June 6 |
| Fall (first frost) | August 14 | September 2 | September 20 |
Dates come from NOAA 1971–2000 freeze probabilities at KREMMLING (33.3 km away); the 50% date is the median year.
Which crops fit a 71-day season in Silverthorne
In Silverthorne (71 frost-free days, a short season), 22 of 56 planner crops fit outright, 8 get two plantings, 9 need an indoor start, 3 need a faster variety, 13 don't reliably mature, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | May 19 | Jul 7–Jul 14 | 29 | no-fit: Needs 80 days; Silverthorne has 29 after Jul 7. | — |
| Pepper | May 12 | Jul 7–Jul 14 | 29 | no-fit: Needs 75 days; Silverthorne has 29 after Jul 7. | — |
| Lettuce | Apr 28 | May 26–Jun 2 | 106 | two-plantings: Plant May 26 and again by Jul 12; both mature before Sep 9. | Jul 12 |
| Carrots | — | Jun 2–Jun 9 | 113 | fits: 70 days to maturity, 113 available after Jun 2. | Jul 1 |
| Cucumber | Jun 2 | Jul 7–Jul 14 | 43 | head-start: Even planted out Jul 7, the outdoor season is about 17 days short; choose an early variety or grow under cover. | — |
| Beans | — | Jun 30–Jul 14 | 57 | tight: Direct-sow only; pick a variety under 57 days. | — |
| Peas | — | Apr 28–Jul 7 | 134 | fits: 65 days to maturity, 134 available after Apr 28. | Jun 22 |
| Zucchini | Jun 9 | Jul 7–Jul 14 | 43 | head-start: Even planted out Jul 7, the outdoor season is about 12 days short; choose an early variety or grow under cover. | — |
| Onion | Mar 31 | May 26–Jun 9 | 106 | fits: 100 days to maturity, 106 available after May 26. | — |
| Spinach | — | Apr 28–Jun 16 | 148 | two-plantings: Plant Apr 28 and again by Jul 31; both mature before Sep 23. | Jul 31 |
| Kale | Apr 14 | May 26–Jun 9 | 120 | fits: 55 days to maturity, 120 available after May 26. | Jul 16 |
| Broccoli | Apr 28 | May 26–Jun 9 | 106 | fits: 80 days to maturity, 106 available after May 26. | Jun 7 |
| Cabbage | Apr 28 | May 26–Jun 9 | 120 | fits: 70 days to maturity, 120 available after May 26. | Jul 1 |
| Radish | — | Apr 28–Jul 21 | 134 | two-plantings: Plant Apr 28 and again by Aug 1; both mature before Sep 9. | Aug 1 |
| Beets | — | Apr 28–Jul 21 | 134 | two-plantings: Plant Apr 28 and again by Jul 2; both mature before Sep 9. | Jul 2 |
| Potatoes | — | Jun 9–Jun 16 | 92 | fits: 90 days to maturity, 92 available after Jun 9. | — |
| Garlic | — | Sep 2 | 176 | overwinter: Plant Sep 2 to Sep 23; harvest the following summer. | Sep 23 |
| Strawberry | — | May 19–Jul 14 | 127 | perennial: A perennial: plant May 19; it fruits from the following year and keeps producing for several years. | — |
| Corn | May 26 | Jun 30–Jul 7 | 43 | no-fit: Needs 75 days; Silverthorne has 43 after Jun 30. | — |
| Pumpkin | Jun 9 | Jul 7–Jul 7 | 36 | no-fit: Needs 100 days; Silverthorne has 36 after Jul 7. | — |
| Cauliflower | May 12 | Jun 16–Jun 30 | 85 | fits: 75 days to maturity, 85 available after Jun 16. | — |
| Swiss Chard | Apr 28 | Jun 9–Jun 9 | 92 | fits: 55 days to maturity, 92 available after Jun 9. | Jul 2 |
| Arugula | — | Apr 28–Jul 21 | 148 | two-plantings: Plant Apr 28 and again by Jul 31; both mature before Sep 23. | Jul 31 |
| Brussel Sprouts | Apr 28 | May 26–Jun 9 | 120 | fits: 100 days to maturity, 120 available after May 26. | Jun 1 |
| Butternut Squash | Jun 9 | Jul 7–Jul 14 | 36 | no-fit: Needs 100 days; Silverthorne has 36 after Jul 7. | — |
| Eggplant | May 5 | Jul 7–Jul 14 | 29 | no-fit: Needs 70 days; Silverthorne has 29 after Jul 7. | — |
| Okra | May 26 | Jun 30–Jul 7 | 50 | head-start: Even planted out Jun 30, the outdoor season is about 5 days short; choose an early variety or grow under cover. | — |
| Basil | May 19 | Jul 14–Jul 14 | 36 | no-fit: Needs 60 days; Silverthorne has 36 after Jul 14. | — |
| Cilantro | — | May 26–Jun 16 | 106 | fits: 50 days to maturity, 106 available after May 26. | Jul 7 |
| Parsley | Apr 14 | Jun 30–Jul 7 | 71 | fits: 70 days to maturity, 71 available after Jun 30. | — |
| Celery | Apr 14 | Jun 30–Jul 14 | 71 | no-fit: Needs 120 days; Silverthorne has 71 after Jun 30. | — |
| Scallions | Apr 14 | May 26–Jun 9 | 120 | fits: 60 days to maturity, 120 available after May 26. | Jul 11 |
| Turnip | — | May 26–Jun 9 | 120 | two-plantings: Plant May 26 and again by Jul 21; both mature before Sep 23. | Jul 21 |
| Kohlrabi | — | May 12–May 26 | 134 | two-plantings: Plant May 12 and again by Jul 16; both mature before Sep 23. | Jul 16 |
| Bok Choy | May 26 | Jun 16–Jun 23 | 85 | fits: 45 days to maturity, 85 available after Jun 16. | Jul 12 |
| Collards | Apr 14 | May 26–Jun 9 | 120 | fits: 60 days to maturity, 120 available after May 26. | Jul 11 |
| Cantaloupe | Jun 9 | Jul 7–Jul 14 | 29 | no-fit: Needs 85 days; Silverthorne has 29 after Jul 7. | — |
| Chives | Mar 31 | Jun 30–Jul 7 | 85 | head-start: Even planted out Jun 30, the outdoor season is about 5 days short; choose an early variety or grow under cover. | — |
| Dill | — | Apr 28–Jul 21 | 134 | two-plantings: Plant Apr 28 and again by Jul 2; both mature before Sep 9. | Jul 2 |
| Oregano | Apr 14 | Jun 30–Jul 7 | 85 | fits: 80 days to maturity, 85 available after Jun 30. | — |
| Rosemary | Mar 31 | Jun 30–Jul 7 | 71 | head-start: Even planted out Jun 30, the outdoor season is about 9 days short; choose an early variety or grow under cover. | — |
| Sage | Apr 28 | Jun 30–Jul 7 | 85 | fits: 75 days to maturity, 85 available after Jun 30. | — |
| Thyme | Apr 14 | Jun 30–Jul 7 | 85 | head-start: Even planted out Jun 30, the outdoor season is about 5 days short; choose an early variety or grow under cover. | — |
| Calendula | May 12 | Jun 9–Jun 23 | 92 | fits: 50 days to maturity, 92 available after Jun 9. | Jul 7 |
| Cosmos | May 26 | Jun 23–Jul 7 | 57 | head-start: Even planted out Jun 23, the outdoor season is about 3 days short; choose an early variety or grow under cover. | — |
| Lavender | Mar 31 | Jun 23–Jul 7 | 92 | fits: 90 days to maturity, 92 available after Jun 23. | — |
| Marigolds | May 12 | Jun 23–Jun 30 | 57 | fits: 50 days to maturity, 57 available after Jun 23. | — |
| Melons | Jun 9 | Jul 7–Jul 14 | 29 | no-fit: Needs 85 days; Silverthorne has 29 after Jul 7. | — |
| Mint | — | Jun 23–Jul 7 | 92 | fits: 90 days to maturity, 92 available after Jun 23. | — |
| Nasturtiums | May 26 | Jun 23–Jun 30 | 57 | fits: 55 days to maturity, 57 available after Jun 23. | — |
| Pole Beans | — | Jun 30–Jul 14 | 50 | tight: Direct-sow only; pick a variety under 50 days. | — |
| Spaghetti Squash | Jun 9 | Jul 7–Jul 14 | 36 | no-fit: Needs 90 days; Silverthorne has 36 after Jul 7. | — |
| Sunflowers | — | Jun 23–Jul 7 | 57 | tight: Direct-sow only; pick a variety under 57 days. | — |
| Tomatillos | Apr 28 | Jun 30–Jul 7 | 36 | no-fit: Needs 75 days; Silverthorne has 36 after Jun 30. | — |
| Watermelon | Jun 9 | Jun 30–Jul 7 | 36 | no-fit: Needs 80 days; Silverthorne has 36 after Jun 30. | — |
| Yellow Squash | Jun 9 | Jul 7–Jul 14 | 43 | head-start: Even planted out Jul 7, the outdoor season is about 12 days short; choose an early variety or grow under cover. | — |
| Zinnias | May 26 | Jun 23–Jul 7 | 57 | head-start: Even planted out Jun 23, the outdoor season is about 3 days short; choose an early variety or grow under cover. | — |
Month by month in Silverthorne
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start the slowest-growing crops indoors: onions, leeks, and celery (10–12 weeks before last frost). |
| March | Start indoors: Chives (Mar 31), Lavender (Mar 31), Onion (Mar 31), Rosemary (Mar 31). |
| April | Start indoors: Celery (Apr 14), Collards (Apr 14), Kale (Apr 14), Oregano (Apr 14), Parsley (Apr 14), Scallions (Apr 14), +8 more. Direct sow from: Arugula (Apr 28), Beets (Apr 28), Dill (Apr 28), Peas (Apr 28), Radish (Apr 28), Spinach (Apr 28). |
| May | Start indoors: Eggplant (May 5), Calendula (May 12), Cauliflower (May 12), Marigolds (May 12), Pepper (May 12), Basil (May 19), +7 more. Direct sow from: Kohlrabi (May 12), Cilantro (May 26), Turnip (May 26). Transplant from: Broccoli (May 26), Brussel Sprouts (May 26), Cabbage (May 26), Collards (May 26), Kale (May 26), Lettuce (May 26), +2 more. Plant: Strawberry (May 19). |
| June | Start indoors: Cucumber (Jun 2), Butternut Squash (Jun 9), Cantaloupe (Jun 9), Melons (Jun 9), Pumpkin (Jun 9), Spaghetti Squash (Jun 9), +3 more. Direct sow from: Carrots (Jun 2), Potatoes (Jun 9), Sunflowers (Jun 23), Beans (Jun 30), Pole Beans (Jun 30). Transplant from: Calendula (Jun 9), Swiss Chard (Jun 9), Bok Choy (Jun 16), Cauliflower (Jun 16), Cosmos (Jun 23), Lavender (Jun 23), +15 more. Last frost around June 23. Last sowing dates: Brussel Sprouts (Jun 1), Broccoli (Jun 7), Peas (Jun 22). |
| July | Transplant from: Butternut Squash (Jul 7), Cantaloupe (Jul 7), Cucumber (Jul 7), Eggplant (Jul 7), Melons (Jul 7), Pepper (Jul 7), +6 more. Last sowing dates: Cabbage (Jul 1), Carrots (Jul 1), Beets (Jul 2), Dill (Jul 2), Swiss Chard (Jul 2), Calendula (Jul 7), +10 more. |
| August | Last sowing dates: Radish (Aug 1). |
| September | Direct sow from: Garlic (Sep 2). First frost around September 2. Last sowing dates: Garlic (Sep 23). |
| October | Harvest remaining cold-hardy crops: kale, carrots, and beets. Plant garlic bulbs for next year. |
| November | Clean up spent plants. Add compost to beds. Rest, review, and plan next year's garden. |
| 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 Silverthorne, CO (ZIP 80498)?
The median last spring frost date for Silverthorne, CO (ZIP code 80498) is around June 23. 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 June 6; one in ten it runs past July 13.
What is the first fall frost date in Silverthorne, CO?
The median first fall frost date for Silverthorne, CO is around September 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 August 14 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Silverthorne, CO?
The frost-free growing season in Silverthorne is about 71 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 Silverthorne (71 frost-free days, a short season), 22 of 56 planner crops fit outright, 8 get two plantings, 9 need an indoor start, 3 need a faster variety, 13 don't reliably mature, 1 crop is perennial.
What USDA hardiness zone is Silverthorne, CO?
Silverthorne, CO is in USDA hardiness zone 5a (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 Silverthorne, CO?
Start tomatoes indoors May 19 and plant out Jul 7 in Silverthorne. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Silverthorne?
Two: plant May 26 and again by Jul 12; both mature before Sep 9.
When do I plant garlic in Silverthorne?
Sep 2 to Sep 23; it overwinters and is ready the following summer.
Can I grow Celery in Silverthorne?
Not reliably outdoors. Needs 120 days; Silverthorne has 71 after Jun 30.
Which nearby ZIP has a longer season?
Evergreen (ZIP 80439) has 98 frost-free days, 27 more than Silverthorne (ZIP 80498). See Evergreen ZIP 80439 frost dates
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