Fall in zone 4aPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 58501 (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, ND (4 miles away).
- Average last spring frostMay 1450% chance of a 32°F freeze after this date
- Average first fall frostSep 2750% chance of a 32°F freeze by this date
- Growing season (frost-free)136 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, 11 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, 11 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 58501 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) | May 1 |
| 50% (the "average" last frost) | May 14 |
| 10% (cautious: only 1 year in 10 freezes later) | May 27 |
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 15 |
| 50% (the "average" first frost) | Sep 27 |
| 90% (late: most years have frozen by now) | Oct 9 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | May 25 | Sep 19 |
| 32°F (freeze) | May 14 | Sep 27 |
| 28°F (hard freeze) | May 3 | Oct 5 |
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 58501
Dates count from your average last spring frost (May 14) and first fall frost (Sep 27). 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 19–Apr 2 | May 21–Jun 4 (transplant) | – |
| Pepper (sweet and hot) | Mar 5–19 | May 28–Jun 11 (transplant) | – |
| Eggplant | Mar 5–19 | May 28–Jun 11 (transplant) | – |
| Tomatillo | Mar 19–Apr 2 | May 21–Jun 4 (transplant) | – |
| Lettuce | Mar 19–Apr 2 | Apr 23–May 14 (transplant) Apr 16–May 28 (sow outdoors) | Aug 2–23 (transplant) Jul 19–Aug 16 (sowing) |
| Spinach | – | Apr 2–23 (sow outdoors) | Aug 2–23 (sowing) |
| Kale | Mar 19–Apr 2 | Apr 16–30 (transplant) Apr 16–30 (sow outdoors) | Jul 5–Aug 2 (transplant) Jun 21–Jul 19 (sowing) |
| Collards | Mar 19–Apr 2 | Apr 16–May 14 (transplant) Apr 16–May 14 (sow outdoors) | Jul 5–Aug 2 (transplant) Jun 21–Jul 19 (sowing) |
| Broccoli | Mar 5–19 | Apr 16–30 (transplant) | Jun 21–Jul 19 (transplant) |
| Cabbage | Mar 5–19 | Apr 16–30 (transplant) | Jun 21–Jul 19 (transplant) |
| Cauliflower | Mar 5–19 | Apr 30–May 14 (transplant) | Jun 21–Jul 19 (transplant) |
| Brussels sprouts | Feb 19–Mar 5 | Apr 16–30 (transplant) | Jun 7–28 (transplant) |
| Kohlrabi | Mar 19–Apr 2 | Apr 16–30 (transplant) Apr 16–30 (sow outdoors) | Jul 19–Aug 2 (sowing) |
| Bok choy / Asian greens | – | Apr 16–30 (sow outdoors) | Aug 2–16 (sowing) |
| Arugula | – | Apr 16–May 14 (sow outdoors) | Aug 2–30 (sowing) |
| Mustard greens | – | Apr 16–May 7 (sow outdoors) | Aug 2–16 (sowing) |
| Swiss chard | Apr 2–16 | Apr 30–May 21 (transplant) Apr 30–May 28 (sow outdoors) | Jul 19–Aug 2 (sowing) |
| Beet | – | Apr 16–May 14 (sow outdoors) | Jul 19–Aug 2 (sowing) |
| Carrot | – | Apr 23–May 21 (sow outdoors) | Jul 5–19 (sowing) |
| Radish | – | Apr 9–May 21 (sow outdoors) | Aug 16–30 (sowing) |
| Turnip | – | Apr 16–May 7 (sow outdoors) | Jul 19–Aug 2 (sowing) |
| Parsnip | – | Apr 23–May 14 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 19–Apr 16 (sow outdoors) | Jul 5–19 (sowing) |
| Onion (bulbing) | Feb 19–Mar 5 | Apr 2–16 (transplant) | – |
| Green onion / scallion | – | Apr 2–30 (sow outdoors) | Jul 19–Aug 2 (sowing) |
| Leek | Feb 19–Mar 5 | Apr 16–30 (transplant) | – |
| Garlic | – | – | Aug 16–Sep 13 (sowing) |
| Shallot | – | Apr 2–16 (transplant) | Aug 16–Sep 13 (sowing) |
| Potato | – | Apr 16–30 (transplant) | Jun 7–21 (transplant) |
| Sweet potato | – | Jun 4–18 (transplant) | – |
| Sweet corn | – | May 21–Jun 4 (sow outdoors) | – |
| Bean, bush (snap) | – | May 21–Jun 4 (sow outdoors) | – |
| Bean, pole | – | May 21–Jun 4 (sow outdoors) | – |
| Lima bean | – | May 28–Jun 11 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Jun 4–25 (sow outdoors) | – |
| Cucumber | Apr 16–23 | May 21–Jun 4 (transplant) May 21–Jun 4 (sow outdoors) | – |
| Summer squash / zucchini | Apr 16–23 | May 21–Jun 4 (transplant) May 21–Jun 4 (sow outdoors) | – |
| Winter squash | Apr 16–23 | May 21–Jun 4 (transplant) May 21–Jun 4 (sow outdoors) | – |
| Pumpkin | – | May 21–Jun 4 (sow outdoors) | – |
| Watermelon | Apr 16–23 | May 28–Jun 11 (transplant) May 28–Jun 11 (sow outdoors) | – |
| Cantaloupe / muskmelon | Apr 16–23 | May 28–Jun 11 (transplant) May 28–Jun 11 (sow outdoors) | – |
| Okra | Apr 2–16 | May 28–Jun 11 (transplant) May 28–Jun 11 (sow outdoors) | – |
| Celery | Feb 19–Mar 5 | May 21–28 (transplant) | – |
| Basil | Apr 2–16 | May 21–Jun 4 (transplant) May 21–Jun 4 (sow outdoors) | – |
| Cilantro | – | Apr 30–May 28 (sow outdoors) | Aug 2–16 (sowing) |
| Parsley | Mar 5–19 | Apr 30–May 14 (transplant) Apr 23–May 14 (sow outdoors) | – |
| Dill | – | May 14–28 (sow outdoors) | Aug 2–16 (sowing) |
| Sunflower | – | May 14–28 (sow outdoors) | – |
| Asparagus (crowns) | – | Apr 16–30 (transplant) | – |
| Rhubarb (crowns) | – | Apr 16–30 (transplant) | – |
| Strawberry (plants) | – | Apr 16–30 (transplant) | Jul 19–Aug 16 (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, ND (NOAA GHCN-Daily ID USW00024011), elevation 1,658 ft, 4.2 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Bismarck WFO, ND | 4 mi | May 14 | Sep 30 |
| Bismarck 2.4 NNW, ND | 5 mi | May 10 | Sep 30 |
| 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 58501
When is the last frost in 58501?
The average (50% chance) last spring freeze of 32°F for ZIP 58501 is May 14. For a more cautious planting date, use May 27, when only 1 year in 10 still sees a later freeze.
When is the first frost in 58501?
The average first fall freeze is September 27. In 1 year in 10 it comes by September 15.
What hardiness zone is 58501?
ZIP 58501 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 58501 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 58504 Bismarck 58503 Bismarck 58558 Menoken 58554 Mandan 58521 58572 58566
Other ZIP codes in Burleigh County
58477 58494 58503 58504 58505 58521 58532 58558 58560 58572 58579 All Burleigh County frost dates · North Dakota frost dates
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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.