Frost Dates & Planting Calendar for Belle Fourche, SD

The average first fall frost in Belle Fourche, SD is September 30, and the average last spring frost is May 10, giving a growing season of about 143 days.

Plan your garden around Belle Fourche, SD's typical frost-free growing season, using NOAA climate normals and a 42-crop planting calendar built for this location.

Last Spring Frost

May 10

Safe May 25 Typical May 10 Risky Apr 27

First Fall Frost

September 30

Safe Sep 16 Typical Sep 30 Risky Oct 13

Growing Season

143 days

Typical last frost to typical first frost.

USDA Hardiness Zone

Zone 4b

Very cold winters, focus on short-season varieties and cold-hardy perennials.

Data: NOAA station BELLE FOURCHE, SD US, 0.1 km away.

— days until the typical last spring frost

How Belle Fourche Compares

Belle Fourche's typical last spring frost (May 10) comes later than in 80% of the 20 South Dakota cities we track.
Its 143-day growing season is 5 days shorter than the South Dakota median of 148 days.
Compared with Spearfish (20 km away), Belle Fourche's last spring frost comes 2 days earlier than Spearfish's, and its first fall frost arrives 2 days earlier.
July is the warmest month (average high 87°F) and January the coldest (average low 13°F).

Monthly Temperatures

Avg. high Avg. temp Avg. low

Planting Calendar

Vegetables
Crop	Start indoors	Direct sow	Transplant	Fall planting	Maturity	Notes
Tomato	Mar 15 – Mar 29	—	May 17 – May 24	—	60–85 days	Start indoors 6-8 weeks before last frost; transplant out 1-2 weeks after last frost once soil has warmed.
Pepper	Mar 1 – Mar 15	—	May 17 – May 31	—	60–90 days	Slow to germinate; start indoors 8-10 weeks before last frost. Transplant only once nights stay above 55F, 1-3 weeks after last frost.
Eggplant	Mar 1 – Mar 15	—	May 24 – May 31	—	65–85 days	Warm-season crop, similar timing to pepper; needs consistently warm soil (65F+) to transplant.
Cucumber	Apr 12 – Apr 19	May 17 – May 24	May 17 – May 24	—	50–65 days	Can be started indoors 3-4 weeks before transplanting, or direct-sown 1-2 weeks after last frost once soil is warm.
Zucchini	Apr 19 – Apr 26	May 17 – May 31	May 17 – May 24	—	45–55 days	Fast-growing squash; direct sow 1-3 weeks after last frost, or start indoors 2-3 weeks early for a head start.
Winter Squash	Apr 12 – Apr 19	May 17 – May 31	May 17 – May 24	—	80–110 days	Long season; direct sow after soil warms, or start indoors 3-4 weeks before last frost in short-season climates.
Pumpkin	—	May 17 – May 31	—	—	90–120 days	Direct sow 1-3 weeks after last frost; back-time from your first fall frost so the 90-120 day maturity window lands before it.
Watermelon	Apr 12 – Apr 19	—	May 24 – May 31	—	70–90 days	Needs warm soil (65F+); start indoors 3-4 weeks before last frost, transplant 2-3 weeks after last frost.
Cantaloupe	Apr 12 – Apr 19	—	May 24 – May 31	—	70–90 days	Same warm-soil requirements as watermelon; avoid disturbing roots when transplanting.
Corn	—	May 10 – May 24	—	—	60–100 days	Direct sow at last frost to 2 weeks after, once soil reaches 60F; does not transplant well. Succession sow every 2 weeks.
Green Bean	—	May 10 – May 24	—	—	50–65 days	Direct sow at last frost to 2 weeks after, once soil has warmed; frost-tender, do not rush.
Pea	—	Mar 29 – Apr 12	—	—	55–70 days	Cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked.
Lettuce	—	Apr 12 – Apr 26	—	Aug 5 – Aug 19	45–60 days	Cold-hardy; direct sow 2-4 weeks before last frost. Also transplantable from indoor starts.
Spinach	—	Mar 29 – Apr 12	—	Aug 5 – Aug 19	40–50 days	Very cold-hardy; direct sow 4-6 weeks before last frost as soon as soil can be worked.
Kale	—	Apr 12 – Apr 26	—	Jul 22 – Aug 5	50–65 days	Cold-hardy; direct sow 2-4 weeks before last frost or start indoors for earlier transplants.
Arugula	—	Apr 12 – Apr 26	—	Aug 19 – Aug 26	30–40 days	Fast-growing, cold-tolerant green; direct sow 2-4 weeks before last frost, succession sow every 2-3 weeks.
Swiss Chard	—	Apr 19 – May 3	—	—	50–60 days	Fairly cold-hardy; direct sow 1-3 weeks before last frost. Tolerates light frost in fall too.
Broccoli	Mar 22 – Apr 5	—	Apr 19 – Apr 26	Jul 29 – Aug 5	55–80 days	Start indoors 5-7 weeks before last frost; transplant out 2-3 weeks before last frost (hardens off to light frost).
Cauliflower	Mar 22 – Apr 5	—	Apr 26 – May 3	Jul 22 – Jul 29	55–85 days	Fussier than broccoli about temperature swings; start indoors 5-7 weeks before last frost, transplant 1-2 weeks before last frost.
Cabbage	Mar 22 – Apr 5	—	Apr 12 – Apr 26	Jul 22 – Aug 5	60–100 days	Cold-hardy; start indoors 5-7 weeks before last frost, transplant 2-4 weeks before last frost.
Brussels Sprouts	Mar 22 – Apr 5	—	Apr 19 – May 3	—	90–110 days	Long-season crop best timed to mature after a light fall frost for sweetest flavor; start indoors 5-7 weeks before last frost.
Carrot	—	Apr 12 – Apr 26	—	Jul 8 – Jul 22	60–80 days	Direct sow only (does not transplant); sow 2-4 weeks before last frost, as soon as soil can be worked.
Beet	—	Apr 12 – Apr 26	—	Jul 22 – Aug 5	50–65 days	Direct sow 2-4 weeks before last frost; tolerates light frost.
Radish	—	Apr 5 – Apr 19	—	Aug 19 – Sep 2	22–30 days	Very fast and cold-hardy; direct sow 3-5 weeks before last frost, as soon as soil can be worked.
Turnip	—	Apr 12 – Apr 26	—	Jul 22 – Aug 5	40–60 days	Cold-hardy; direct sow 2-4 weeks before last frost.
Onion	Mar 1 – Mar 15	—	Apr 12 – Apr 26	—	90–120 days	Start seeds indoors 8-10 weeks before last frost (or use sets/transplants); set out 2-4 weeks before last frost, very cold-tolerant as seedlings.
Garlic	—	—	—	Sep 2 – Sep 16	240–270 days	Fall-planted crop only; not planted in spring in most climates.
Potato	—	Apr 12 – Apr 26	—	—	70–120 days	Plant seed potatoes 2-4 weeks before last frost, as soon as soil can be worked and is above 45F; light frost on emerging foliage is usually tolerated.
Sweet Potato	—	—	May 24 – Jun 7	—	90–120 days	Set out slips 2-4 weeks after last frost once soil is thoroughly warm (65F+); very frost/cold sensitive.
Asparagus	—	—	Apr 12 – Apr 26	—	730–1095 days	Perennial; plant crowns 2-4 weeks before last frost as soon as soil can be worked. Takes 2-3 years to full production.

Herbs
Crop	Start indoors	Direct sow	Transplant	Fall planting	Maturity	Notes
Basil	Mar 29 – Apr 5	—	May 17 – May 24	—	50–70 days	Very frost/cold sensitive; start indoors 5-6 weeks before last frost, transplant only after all danger of frost (1-2 weeks after) and nights stay warm.
Cilantro	—	Apr 19 – May 3	—	Aug 5 – Aug 19	45–70 days	Cool-season, bolts in heat; direct sow 1-3 weeks before last frost, succession sow through spring.
Parsley	Mar 15 – Mar 29	—	Apr 26 – May 3	—	70–90 days	Slow to germinate; start indoors 6-8 weeks before last frost, transplant 1-2 weeks before last frost (biennial, cold-tolerant).
Dill	—	Apr 19 – May 3	—	—	40–60 days	Taprooted, does not transplant well; direct sow 1-3 weeks before last frost, succession sow through summer.
Oregano	Mar 15 – Mar 29	—	May 10 – May 17	—	80–90 days	Perennial herb; start indoors 6-8 weeks before last frost, transplant around/just after last frost date.
Thyme	Mar 15 – Mar 29	—	May 10 – May 17	—	85–95 days	Perennial herb, slow from seed; start indoors 6-8 weeks before last frost, transplant around/after last frost.

Flowers
Crop	Start indoors	Direct sow	Transplant	Fall planting	Maturity	Notes
Sunflower	—	May 17 – May 31	—	—	70–100 days	Direct sow 1-3 weeks after last frost once soil has warmed; taprooted, resents transplanting.
Zinnia	Apr 12 – Apr 19	May 17 – May 31	May 17 – May 24	—	60–70 days	Frost-tender; direct sow 1-3 weeks after last frost, or start indoors 3-4 weeks early for earlier blooms.
Marigold	Mar 29 – Apr 12	—	May 17 – May 24	—	45–60 days	Frost-tender; start indoors 4-6 weeks before last frost, transplant after all frost danger has passed.
Cosmos	Apr 12 – Apr 19	May 17 – May 31	May 17 – May 24	—	60–90 days	Easy from direct seed 1-3 weeks after last frost; can also start indoors 3-4 weeks early.
Nasturtium	—	May 17 – May 31	—	—	50–65 days	Frost-tender, resents root disturbance; direct sow 1-3 weeks after last frost once soil has warmed.
Dahlia	—	—	May 17 – May 31	—	90–120 days	Plant tubers 1-3 weeks after last frost once soil is warm (60F+); very frost-sensitive.

Date ranges are estimates based on university extension guidelines and this city's NOAA frost normals — not a guarantee. Scroll to see all columns on narrow screens.

Frequently Asked Questions

When is the last frost in Belle Fourche, SD?

Based on 1991–2020 NOAA climate normals for the BELLE FOURCHE, SD US station, the last spring frost in Belle Fourche typically falls around May 10. A cautious gardener might wait until May 25 (only a 10% chance of a later frost), while April 27 marks an earlier, higher-risk planting date.

When is the first frost in Belle Fourche, SD in fall?

The first fall frost in Belle Fourche typically arrives around September 30. To stay safe, assume frost could start as early as September 16; in milder years it can hold off until October 13.

How long is the growing season in Belle Fourche, SD?

Belle Fourche's average frost-free growing season is about 143 days, running from the typical last spring frost (May 10) to the typical first fall frost (September 30).

What USDA hardiness zone is Belle Fourche, SD in?

Belle Fourche, SD is in USDA plant hardiness zone 4b, per the USDA's 2023 Plant Hardiness Zone Map. Very cold winters, focus on short-season varieties and cold-hardy perennials.