Frost Dates for Spearfish, SD 57783
Last spring frost May 10 · First fall frost September 23 · 136 frost-free days · USDA Zone 5b
ZIP 57783 has about 17,200 people, the largest of 2 ZIP codes in Spearfish.
Moderate season: 136 frost-free days. Spring frost risk spans April 27–May 23 (26 days). Fall frost risk spans September 11–October 4 (23 days).
Frost probability for 57783
| Frost | 10% | 50% | 90% |
|---|---|---|---|
| Spring (last frost) | May 23 | May 10 | April 27 |
| Fall (first frost) | September 11 | September 23 | October 4 |
Dates come from NOAA 1971–2000 freeze probabilities at BELLE FOURCHE (23.0 km away); the 50% date is the median year.
Frost dates by ZIP code in Spearfish, SD
| ZIP | Last spring frost (50%) | First fall frost (50%) | Zone |
|---|---|---|---|
| 57783 | May 10 | September 23 | 5b |
| 57799 | May 10 | September 23 | 5b (est.) |
Which crops fit a 136-day season in Spearfish
In Spearfish (136 frost-free days, a moderate season), 39 of 56 planner crops fit outright, 16 get two plantings, 1 crop is perennial.
| Crop | Start indoors | Plant out / sow | Days you have | Verdict | Last sow date |
|---|---|---|---|---|---|
| Tomato | Apr 5 | May 24–May 31 | 94 | fits: 80 days to maturity, 94 available after May 24. | — |
| Pepper | Mar 29 | May 24–May 31 | 94 | fits: 75 days to maturity, 94 available after May 24. | May 29 |
| Lettuce | Mar 15 | Apr 12–Apr 19 | 171 | two-plantings: Plant Apr 12 and again by Aug 2; both mature before Sep 30. | Aug 2 |
| Carrots | — | Apr 19–Apr 26 | 178 | fits: 70 days to maturity, 178 available after Apr 19. | Jul 22 |
| Cucumber | Apr 19 | May 24–May 31 | 108 | fits: 60 days to maturity, 108 available after May 24. | Jun 27 |
| Beans | — | May 17–May 31 | 122 | fits: 60 days to maturity, 122 available after May 17. | Jul 4 |
| Peas | — | Mar 15–May 24 | 199 | fits: 65 days to maturity, 199 available after Mar 15. | Jul 13 |
| Zucchini | Apr 26 | May 24–May 31 | 108 | fits: 55 days to maturity, 108 available after May 24. | Jul 2 |
| Onion | Feb 15 | Apr 12–Apr 26 | 171 | fits: 100 days to maturity, 171 available after Apr 12. | — |
| Spinach | — | Mar 15–May 3 | 213 | two-plantings: Plant Mar 15 and again by Aug 21; both mature before Oct 14. | Aug 21 |
| Kale | Mar 1 | Apr 12–Apr 26 | 185 | two-plantings: Plant Apr 12 and again by Aug 6; both mature before Oct 14. | Aug 6 |
| Broccoli | Mar 15 | Apr 12–Apr 26 | 171 | fits: 80 days to maturity, 171 available after Apr 12. | Jun 28 |
| Cabbage | Mar 15 | Apr 12–Apr 26 | 185 | fits: 70 days to maturity, 185 available after Apr 12. | Jul 22 |
| Radish | — | Mar 15–Jun 7 | 199 | two-plantings: Plant Mar 15 and again by Aug 22; both mature before Sep 30. | Aug 22 |
| Beets | — | Mar 15–Jun 7 | 199 | two-plantings: Plant Mar 15 and again by Jul 23; both mature before Sep 30. | Jul 23 |
| Potatoes | — | Apr 26–May 3 | 157 | fits: 90 days to maturity, 157 available after Apr 26. | — |
| Garlic | — | Sep 23 | 241 | overwinter: Plant Sep 23 to Oct 14; harvest the following summer. | Oct 14 |
| Strawberry | — | Apr 5–May 31 | 192 | perennial: A perennial: plant Apr 5; it fruits from the following year and keeps producing for several years. | — |
| Corn | Apr 12 | May 17–May 24 | 108 | fits: 75 days to maturity, 108 available after May 17. | Jun 5 |
| Pumpkin | Apr 26 | May 24–May 24 | 101 | fits: 100 days to maturity, 101 available after May 24. | — |
| Cauliflower | Mar 29 | May 3–May 17 | 150 | fits: 75 days to maturity, 150 available after May 3. | Jul 3 |
| Swiss Chard | Mar 15 | Apr 26–Apr 26 | 157 | two-plantings: Plant Apr 26 and again by Jul 23; both mature before Sep 30. | Jul 23 |
| Arugula | — | Mar 15–Jun 7 | 213 | two-plantings: Plant Mar 15 and again by Aug 21; both mature before Oct 14. | Aug 21 |
| Brussel Sprouts | Mar 15 | Apr 12–Apr 26 | 185 | fits: 100 days to maturity, 185 available after Apr 12. | Jun 22 |
| Butternut Squash | Apr 26 | May 24–May 31 | 101 | fits: 100 days to maturity, 101 available after May 24. | — |
| Eggplant | Mar 22 | May 24–May 31 | 94 | fits: 70 days to maturity, 94 available after May 24. | Jun 3 |
| Okra | Apr 12 | May 17–May 24 | 115 | fits: 55 days to maturity, 115 available after May 17. | Jul 2 |
| Basil | Apr 5 | May 31–May 31 | 101 | fits: 60 days to maturity, 101 available after May 31. | Jun 27 |
| Cilantro | — | Apr 12–May 3 | 171 | two-plantings: Plant Apr 12 and again by Jul 28; both mature before Sep 30. | Jul 28 |
| Parsley | Mar 1 | May 17–May 24 | 136 | fits: 70 days to maturity, 136 available after May 17. | Jul 8 |
| Celery | Mar 1 | May 17–May 31 | 136 | fits: 120 days to maturity, 136 available after May 17. | May 19 |
| Scallions | Mar 1 | Apr 12–Apr 26 | 185 | two-plantings: Plant Apr 12 and again by Aug 1; both mature before Oct 14. | Aug 1 |
| Turnip | — | Apr 12–Apr 26 | 185 | two-plantings: Plant Apr 12 and again by Aug 11; both mature before Oct 14. | Aug 11 |
| Kohlrabi | — | Mar 29–Apr 12 | 199 | two-plantings: Plant Mar 29 and again by Aug 6; both mature before Oct 14. | Aug 6 |
| Bok Choy | Apr 12 | May 3–May 10 | 150 | two-plantings: Plant May 3 and again by Aug 2; both mature before Sep 30. | Aug 2 |
| Collards | Mar 1 | Apr 12–Apr 26 | 185 | two-plantings: Plant Apr 12 and again by Aug 1; both mature before Oct 14. | Aug 1 |
| Cantaloupe | Apr 26 | May 24–May 31 | 94 | fits: 85 days to maturity, 94 available after May 24. | — |
| Chives | Feb 15 | May 17–May 24 | 150 | fits: 90 days to maturity, 150 available after May 17. | — |
| Dill | — | Mar 15–Jun 7 | 199 | two-plantings: Plant Mar 15 and again by Jul 23; both mature before Sep 30. | Jul 23 |
| Oregano | Mar 1 | May 17–May 24 | 150 | fits: 80 days to maturity, 150 available after May 17. | — |
| Rosemary | Feb 15 | May 17–May 24 | 136 | fits: 80 days to maturity, 136 available after May 17. | — |
| Sage | Mar 15 | May 17–May 24 | 150 | fits: 75 days to maturity, 150 available after May 17. | — |
| Thyme | Mar 1 | May 17–May 24 | 150 | fits: 90 days to maturity, 150 available after May 17. | — |
| Calendula | Mar 29 | Apr 26–May 10 | 157 | two-plantings: Plant Apr 26 and again by Jul 28; both mature before Sep 30. | Jul 28 |
| Cosmos | Apr 12 | May 10–May 24 | 122 | fits: 60 days to maturity, 122 available after May 10. | Jun 27 |
| Lavender | Feb 15 | May 10–May 24 | 157 | fits: 90 days to maturity, 157 available after May 10. | — |
| Marigolds | Mar 29 | May 10–May 17 | 122 | two-plantings: Plant May 10 and again by Jul 7; both mature before Sep 9. | Jul 7 |
| Melons | Apr 26 | May 24–May 31 | 94 | fits: 85 days to maturity, 94 available after May 24. | — |
| Mint | — | May 10–May 24 | 157 | fits: 90 days to maturity, 157 available after May 10. | — |
| Nasturtiums | Apr 12 | May 10–May 17 | 122 | fits: 55 days to maturity, 122 available after May 10. | Jul 2 |
| Pole Beans | — | May 17–May 31 | 115 | fits: 65 days to maturity, 115 available after May 17. | Jun 22 |
| Spaghetti Squash | Apr 26 | May 24–May 31 | 101 | fits: 90 days to maturity, 101 available after May 24. | — |
| Sunflowers | — | May 10–May 24 | 122 | fits: 70 days to maturity, 122 available after May 10. | Jun 17 |
| Tomatillos | Mar 15 | May 17–May 24 | 101 | fits: 75 days to maturity, 101 available after May 17. | May 29 |
| Watermelon | Apr 26 | May 17–May 24 | 101 | fits: 80 days to maturity, 101 available after May 17. | May 24 |
| Yellow Squash | Apr 26 | May 24–May 31 | 108 | fits: 55 days to maturity, 108 available after May 24. | Jul 2 |
| Zinnias | Apr 12 | May 10–May 24 | 122 | fits: 60 days to maturity, 122 available after May 10. | Jun 27 |
Month by month in Spearfish
| Month | What to do |
|---|---|
| January | Plan your garden layout and order seeds. Research varieties suited to your frost dates. |
| February | Start indoors: Chives (Feb 15), Lavender (Feb 15), Onion (Feb 15), Rosemary (Feb 15). |
| March | Start indoors: Celery (Mar 1), Collards (Mar 1), Kale (Mar 1), Oregano (Mar 1), Parsley (Mar 1), Scallions (Mar 1), +13 more. Direct sow from: Arugula (Mar 15), Beets (Mar 15), Dill (Mar 15), Peas (Mar 15), Radish (Mar 15), Spinach (Mar 15), +1 more. |
| April | Start indoors: Basil (Apr 5), Tomato (Apr 5), Bok Choy (Apr 12), Corn (Apr 12), Cosmos (Apr 12), Nasturtiums (Apr 12), +11 more. Direct sow from: Cilantro (Apr 12), Turnip (Apr 12), Carrots (Apr 19), Potatoes (Apr 26). Transplant from: Broccoli (Apr 12), Brussel Sprouts (Apr 12), Cabbage (Apr 12), Collards (Apr 12), Kale (Apr 12), Lettuce (Apr 12), +4 more. Plant: Strawberry (Apr 5). |
| May | Direct sow from: Sunflowers (May 10), Beans (May 17), Pole Beans (May 17). Transplant from: Bok Choy (May 3), Cauliflower (May 3), Cosmos (May 10), Lavender (May 10), Marigolds (May 10), Mint (May 10), +25 more. Last frost around May 10. Last sowing dates: Celery (May 19), Watermelon (May 24), Pepper (May 29), Tomatillos (May 29). |
| June | Last sowing dates: Eggplant (Jun 3), Corn (Jun 5), Sunflowers (Jun 17), Brussel Sprouts (Jun 22), Pole Beans (Jun 22), Basil (Jun 27), +4 more. |
| July | Last sowing dates: Nasturtiums (Jul 2), Okra (Jul 2), Yellow Squash (Jul 2), Zucchini (Jul 2), Cauliflower (Jul 3), Beans (Jul 4), +10 more. |
| August | Last sowing dates: Collards (Aug 1), Scallions (Aug 1), Bok Choy (Aug 2), Lettuce (Aug 2), Kale (Aug 6), Kohlrabi (Aug 6), +4 more. |
| September | Direct sow from: Garlic (Sep 23). First frost around September 23. |
| October | Last sowing dates: Garlic (Oct 14). |
| 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 Spearfish, SD (ZIP 57783)?
The median last spring frost date for Spearfish, SD (ZIP code 57783) is around May 10. 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 27; one in ten it runs past May 23.
What is the first fall frost date in Spearfish, SD?
The median first fall frost date for Spearfish, SD is around September 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 September 11 in the earliest one-in-ten years, so cover tomatoes and peppers from then.
How long is the growing season in Spearfish, SD?
The frost-free growing season in Spearfish is about 136 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 Spearfish (136 frost-free days, a moderate season), 39 of 56 planner crops fit outright, 16 get two plantings, 1 crop is perennial.
What USDA hardiness zone is Spearfish, SD?
Spearfish, SD is in USDA hardiness zone 5b (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 Spearfish, SD?
Start tomatoes indoors Apr 5 and plant out May 24 in Spearfish. The planner uses the local median last frost and this crop's indoor-start and transplant offsets.
How many plantings of lettuce fit in Spearfish?
Two: plant Apr 12 and again by Aug 2; both mature before Sep 30.
When do I plant garlic in Spearfish?
Sep 23 to Oct 14; it overwinters and is ready the following summer.
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