Fall in zone 4aPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 58503 (Bismarck, ND)
Average last spring and first fall frost dates with 10%, 50% and 90% odds, from NOAA's 1991–2020 climate normals for the nearest weather station, Bismarck 2.4 NNW, ND (5 miles away).
- Average last spring frostMay 1050% chance of a 32°F freeze after this date
- Average first fall frostSep 3050% chance of a 32°F freeze by this date
- Growing season (frost-free)142 daysmedian, 32°F threshold
- USDA hardiness zone4a-30 to -25°F avg. coldest night
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This week in your yard
As of Oct 18, 2026, from your frost dates, zone and soil temperature. Lawn timing · Vegetables · Pruning · Plants
Soil temperature now
2-inch depth
49°F Below 50°F
24-hour average · latest 50°F, as of Oct 18, 2:00 AM CDT
Measured at USDA NRCS SCAN station Mandan #1, 12 mi away. Daily averages: Thu 50°, Fri 49°, Sat 48°.
4-inch depth
49°F Below 50°F
24-hour average · latest 49°F, as of Oct 18, 2:00 AM CDT
Measured at USDA NRCS SCAN station Mandan #1, 12 mi away. Daily averages: Thu 49°, Fri 48°, Sat 49°.
Fall: Texas A&M AgriLife times fall pre-emergent (for winter weeds such as annual bluegrass) to soil cooling to about 70°F for several days. The 50–55°F band is the spring trigger. Always read and follow the product label.
7-day forecast and frost risk
The latest National Weather Service 7-day forecast and any Frost Advisory or Freeze Warning for 58503 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 49°F at 4 inches. Fall pre-emergent window is mostly past. Next: spring, when soil reaches 50°F (typically mid-April to early May).
Fertilizer window
Lawn region: North (cool-season). Timing only; always follow the product label.
- Kentucky bluegrass (cool-season): Early fall: Around Labor Day (late August–September); Late fall: Late October–November, before the ground freezes; Late spring: Optional around Memorial Day. Avoid: Early-spring and midsummer feeding (pushes top growth, favors crabgrass).
Plant now
No vegetable planting windows are open this week.
Prune now
No frost-timed pruning windows are open this week.
Spring-flowering shrubs are pruned right after their flowers fade, not by date. See the pruning guide.
Last spring frost odds
| Chance of a 32°F freeze after this date | Date |
|---|---|
| 90% (early: most years still freeze after this) | Apr 30 |
| 50% (the "average" last frost) | May 10 |
| 10% (cautious: only 1 year in 10 freezes later) | May 23 |
Most gardeners plant frost-tender crops (tomatoes, peppers, basil) after the 50% date, and closer to the 10% date for less risk.
First fall frost odds
| Chance the first 32°F freeze has happened by this date | Date |
|---|---|
| 10% (early: 1 year in 10 freezes this soon) | Sep 16 |
| 50% (the "average" first frost) | Sep 30 |
| 90% (late: most years have frozen by now) | Oct 13 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | May 20 | Sep 21 |
| 32°F (freeze) | May 10 | Sep 30 |
| 28°F (hard freeze) | May 1 | Oct 9 |
n/a means NOAA did not publish a date at that threshold for this station (usually because it rarely gets that cold).
Vegetable planting calendar for 58503
Dates count from your average last spring frost (May 10) and first fall frost (Sep 30). Half of years have a frost after the spring date, so give tender crops (tomatoes, peppers, squash) some slack.
| Crop | Start indoors | Spring planting | Fall planting |
|---|---|---|---|
| Tomato | Mar 15–29 | May 17–31 (transplant) | – |
| Pepper (sweet and hot) | Mar 1–15 | May 24–Jun 7 (transplant) | – |
| Eggplant | Mar 1–15 | May 24–Jun 7 (transplant) | – |
| Tomatillo | Mar 15–29 | May 17–31 (transplant) | – |
| Lettuce | Mar 15–29 | Apr 19–May 10 (transplant) Apr 12–May 24 (sow outdoors) | Aug 5–26 (transplant) Jul 22–Aug 19 (sowing) |
| Spinach | – | Mar 29–Apr 19 (sow outdoors) | Aug 5–26 (sowing) |
| Kale | Mar 15–29 | Apr 12–26 (transplant) Apr 12–26 (sow outdoors) | Jul 8–Aug 5 (transplant) Jun 24–Jul 22 (sowing) |
| Collards | Mar 15–29 | Apr 12–May 10 (transplant) Apr 12–May 10 (sow outdoors) | Jul 8–Aug 5 (transplant) Jun 24–Jul 22 (sowing) |
| Broccoli | Mar 1–15 | Apr 12–26 (transplant) | Jun 24–Jul 22 (transplant) |
| Cabbage | Mar 1–15 | Apr 12–26 (transplant) | Jun 24–Jul 22 (transplant) |
| Cauliflower | Mar 1–15 | Apr 26–May 10 (transplant) | Jun 24–Jul 22 (transplant) |
| Brussels sprouts | Feb 15–Mar 1 | Apr 12–26 (transplant) | Jun 10–Jul 1 (transplant) |
| Kohlrabi | Mar 15–29 | Apr 12–26 (transplant) Apr 12–26 (sow outdoors) | Jul 22–Aug 5 (sowing) |
| Bok choy / Asian greens | – | Apr 12–26 (sow outdoors) | Aug 5–19 (sowing) |
| Arugula | – | Apr 12–May 10 (sow outdoors) | Aug 5–Sep 2 (sowing) |
| Mustard greens | – | Apr 12–May 3 (sow outdoors) | Aug 5–19 (sowing) |
| Swiss chard | Mar 29–Apr 12 | Apr 26–May 17 (transplant) Apr 26–May 24 (sow outdoors) | Jul 22–Aug 5 (sowing) |
| Beet | – | Apr 12–May 10 (sow outdoors) | Jul 22–Aug 5 (sowing) |
| Carrot | – | Apr 19–May 17 (sow outdoors) | Jul 8–22 (sowing) |
| Radish | – | Apr 5–May 17 (sow outdoors) | Aug 19–Sep 2 (sowing) |
| Turnip | – | Apr 12–May 3 (sow outdoors) | Jul 22–Aug 5 (sowing) |
| Parsnip | – | Apr 19–May 10 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 15–Apr 12 (sow outdoors) | Jul 8–22 (sowing) |
| Onion (bulbing) | Feb 15–Mar 1 | Mar 29–Apr 12 (transplant) | – |
| Green onion / scallion | – | Mar 29–Apr 26 (sow outdoors) | Jul 22–Aug 5 (sowing) |
| Leek | Feb 15–Mar 1 | Apr 12–26 (transplant) | – |
| Garlic | – | – | Aug 19–Sep 16 (sowing) |
| Shallot | – | Mar 29–Apr 12 (transplant) | Aug 19–Sep 16 (sowing) |
| Potato | – | Apr 12–26 (transplant) | Jun 10–24 (transplant) |
| Sweet potato | – | May 31–Jun 14 (transplant) | – |
| Sweet corn | – | May 17–31 (sow outdoors) | – |
| Bean, bush (snap) | – | May 17–31 (sow outdoors) | – |
| Bean, pole | – | May 17–31 (sow outdoors) | – |
| Lima bean | – | May 24–Jun 7 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 31–Jun 21 (sow outdoors) | – |
| Cucumber | Apr 12–19 | May 17–31 (transplant) May 17–31 (sow outdoors) | – |
| Summer squash / zucchini | Apr 12–19 | May 17–31 (transplant) May 17–31 (sow outdoors) | – |
| Winter squash | Apr 12–19 | May 17–31 (transplant) May 17–31 (sow outdoors) | – |
| Pumpkin | – | May 17–31 (sow outdoors) | – |
| Watermelon | Apr 12–19 | May 24–Jun 7 (transplant) May 24–Jun 7 (sow outdoors) | – |
| Cantaloupe / muskmelon | Apr 12–19 | May 24–Jun 7 (transplant) May 24–Jun 7 (sow outdoors) | – |
| Okra | Mar 29–Apr 12 | May 24–Jun 7 (transplant) May 24–Jun 7 (sow outdoors) | – |
| Celery | Feb 15–Mar 1 | May 17–24 (transplant) | – |
| Basil | Mar 29–Apr 12 | May 17–31 (transplant) May 17–31 (sow outdoors) | – |
| Cilantro | – | Apr 26–May 24 (sow outdoors) | Aug 5–19 (sowing) |
| Parsley | Mar 1–15 | Apr 26–May 10 (transplant) Apr 19–May 10 (sow outdoors) | – |
| Dill | – | May 10–24 (sow outdoors) | Aug 5–19 (sowing) |
| Sunflower | – | May 10–24 (sow outdoors) | – |
| Asparagus (crowns) | – | Apr 12–26 (transplant) | – |
| Rhubarb (crowns) | – | Apr 12–26 (transplant) | – |
| Strawberry (plants) | – | Apr 12–26 (transplant) | Jul 22–Aug 19 (transplant) |
Typical ranges from university extension planting calendars, adjusted to your frost dates. Probabilities, not guarantees. Fall windows that would overlap spring planting are left out, as are fall crops of frost-tender plants where the frost-free season is under 210 days.
Where these numbers come from
Station: Bismarck 2.4 NNW, ND (NOAA GHCN-Daily ID USC00320817), elevation 1,831 ft, 5.4 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Bismarck WFO, ND | 9 mi | May 14 | Sep 30 |
| Bismarck, ND | 9 mi | May 14 | Sep 27 |
| Mandan EXP STN, ND | 10 mi | May 13 | Sep 27 |
The average last-frost dates of these stations span 4 days, a rough guide to local variation. See data sources & methods.
Frost questions for 58503
When is the last frost in 58503?
The average (50% chance) last spring freeze of 32°F for ZIP 58503 is May 10. For a more cautious planting date, use May 23, when only 1 year in 10 still sees a later freeze.
When is the first frost in 58503?
The average first fall freeze is September 30. In 1 year in 10 it comes by September 16.
What hardiness zone is 58503?
ZIP 58503 is in USDA zone 4a (-30 to -25°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 58503 right now?
This page shows the latest 2-inch and 4-inch soil temperature from the nearest public soil station (USDA SCAN, NOAA USCRN or TexMesonet), or a labeled estimate when no station is close, against the 50–55°F spring pre-emergent band.
Nearby ZIP codes
58505 Bismarck 58501 Bismarck 58521 58504 Bismarck 58558 Menoken 58554 Mandan 58579 Wilton 58572
Other ZIP codes in Burleigh County
58477 58494 58501 58504 58505 58521 58532 58558 58560 58572 58579 All Burleigh County frost dates · North Dakota frost dates
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Weekly yard timing, plus frost and soil-temperature alerts for your ZIP code.
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Free. One weekly email plus alerts when your ZIP has a frost or a soil-temperature change worth acting on. After you submit, Kit (our email provider) sends a confirmation email: check your email and click the link to confirm. You aren't subscribed until you do. We collect only your email address and ZIP, sent to Kit to deliver The Dial. Unsubscribe anytime.