Fall in zone 4bPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 59003 (Ashland, MT)
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, Sonnette 7 SW, MT (18 miles away).
- Average last spring frostMay 2550% chance of a 32°F freeze after this date
- Average first fall frostSep 1950% chance of a 32°F freeze by this date
- Growing season (frost-free)115 daysmedian, 32°F threshold
- USDA hardiness zone4b-25 to -20°F avg. coldest night
Get The Dial for 59003 (Ashland)
Frost and freeze alerts from the NWS forecast for 59003, the spring soil-temperature heads-up for pre-emergent, and a short weekly yard-timing email.
- Freeze alerts
- Soil-temp heads-up
- Weekly yard to-dos
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.
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
No soil station with a fresh reading within 62 miles.
4-inch depth
No soil station with a fresh reading within 62 miles.
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 59003 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
No soil reading near this ZIP. Typical extension timing for your region: spring mid-April to mid-May.
Fertilizer window
Lawn region: Mountain West and High Plains. 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 12 |
| 50% (the "average" last frost) | May 25 |
| 10% (cautious: only 1 year in 10 freezes later) | Jun 7 |
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 1 |
| 50% (the "average" first frost) | Sep 19 |
| 90% (late: most years have frozen by now) | Oct 1 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Jun 7 | Sep 6 |
| 32°F (freeze) | May 25 | Sep 19 |
| 28°F (hard freeze) | May 14 | Sep 29 |
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 59003
Dates count from your average last spring frost (May 25) and first fall frost (Sep 19). 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 30–Apr 13 | Jun 1–15 (transplant) | – |
| Pepper (sweet and hot) | Mar 16–30 | Jun 8–22 (transplant) | – |
| Eggplant | Mar 16–30 | Jun 8–22 (transplant) | – |
| Tomatillo | Mar 30–Apr 13 | Jun 1–15 (transplant) | – |
| Lettuce | Mar 30–Apr 13 | May 4–25 (transplant) Apr 27–Jun 8 (sow outdoors) | Jul 25–Aug 15 (transplant) Jul 11–Aug 8 (sowing) |
| Spinach | – | Apr 13–May 4 (sow outdoors) | Jul 25–Aug 15 (sowing) |
| Kale | Mar 30–Apr 13 | Apr 27–May 11 (transplant) Apr 27–May 11 (sow outdoors) | Jun 27–Jul 25 (transplant) Jun 13–Jul 11 (sowing) |
| Collards | Mar 30–Apr 13 | Apr 27–May 25 (transplant) Apr 27–May 25 (sow outdoors) | Jun 27–Jul 25 (transplant) Jun 13–Jul 11 (sowing) |
| Broccoli | Mar 16–30 | Apr 27–May 11 (transplant) | Jun 13–Jul 11 (transplant) |
| Cabbage | Mar 16–30 | Apr 27–May 11 (transplant) | Jun 13–Jul 11 (transplant) |
| Cauliflower | Mar 16–30 | May 11–25 (transplant) | Jun 13–Jul 11 (transplant) |
| Brussels sprouts | Mar 2–16 | Apr 27–May 11 (transplant) | May 30–Jun 20 (transplant) |
| Kohlrabi | Mar 30–Apr 13 | Apr 27–May 11 (transplant) Apr 27–May 11 (sow outdoors) | Jul 11–25 (sowing) |
| Bok choy / Asian greens | – | Apr 27–May 11 (sow outdoors) | Jul 25–Aug 8 (sowing) |
| Arugula | – | Apr 27–May 25 (sow outdoors) | Jul 25–Aug 22 (sowing) |
| Mustard greens | – | Apr 27–May 18 (sow outdoors) | Jul 25–Aug 8 (sowing) |
| Swiss chard | Apr 13–27 | May 11–Jun 1 (transplant) May 11–Jun 8 (sow outdoors) | Jul 11–25 (sowing) |
| Beet | – | Apr 27–May 25 (sow outdoors) | Jul 11–25 (sowing) |
| Carrot | – | May 4–Jun 1 (sow outdoors) | Jun 27–Jul 11 (sowing) |
| Radish | – | Apr 20–Jun 1 (sow outdoors) | Aug 8–22 (sowing) |
| Turnip | – | Apr 27–May 18 (sow outdoors) | Jul 11–25 (sowing) |
| Parsnip | – | May 4–25 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 30–Apr 27 (sow outdoors) | Jun 27–Jul 11 (sowing) |
| Onion (bulbing) | Mar 2–16 | Apr 13–27 (transplant) | – |
| Green onion / scallion | – | Apr 13–May 11 (sow outdoors) | Jul 11–25 (sowing) |
| Leek | Mar 2–16 | Apr 27–May 11 (transplant) | – |
| Garlic | – | – | Aug 8–Sep 5 (sowing) |
| Shallot | – | Apr 13–27 (transplant) | Aug 8–Sep 5 (sowing) |
| Potato | – | Apr 27–May 11 (transplant) | May 30–Jun 13 (transplant) |
| Sweet potato | – | Jun 15–29 (transplant) | – |
| Sweet corn | – | Jun 1–15 (sow outdoors) | – |
| Bean, bush (snap) | – | Jun 1–15 (sow outdoors) | – |
| Bean, pole | – | Jun 1–15 (sow outdoors) | – |
| Lima bean | – | Jun 8–22 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Jun 15–Jul 6 (sow outdoors) | – |
| Cucumber | Apr 27–May 4 | Jun 1–15 (transplant) Jun 1–15 (sow outdoors) | – |
| Summer squash / zucchini | Apr 27–May 4 | Jun 1–15 (transplant) Jun 1–15 (sow outdoors) | – |
| Winter squash | Apr 27–May 4 | Jun 1–15 (transplant) Jun 1–15 (sow outdoors) | – |
| Pumpkin | – | Jun 1–15 (sow outdoors) | – |
| Watermelon | Apr 27–May 4 | Jun 8–22 (transplant) Jun 8–22 (sow outdoors) | – |
| Cantaloupe / muskmelon | Apr 27–May 4 | Jun 8–22 (transplant) Jun 8–22 (sow outdoors) | – |
| Okra | Apr 13–27 | Jun 8–22 (transplant) Jun 8–22 (sow outdoors) | – |
| Celery | Mar 2–16 | Jun 1–8 (transplant) | – |
| Basil | Apr 13–27 | Jun 1–15 (transplant) Jun 1–15 (sow outdoors) | – |
| Cilantro | – | May 11–Jun 8 (sow outdoors) | Jul 25–Aug 8 (sowing) |
| Parsley | Mar 16–30 | May 11–25 (transplant) May 4–25 (sow outdoors) | – |
| Dill | – | May 25–Jun 8 (sow outdoors) | Jul 25–Aug 8 (sowing) |
| Sunflower | – | May 25–Jun 8 (sow outdoors) | – |
| Asparagus (crowns) | – | Apr 27–May 11 (transplant) | – |
| Rhubarb (crowns) | – | Apr 27–May 11 (transplant) | – |
| Strawberry (plants) | – | Apr 27–May 11 (transplant) | Jul 11–Aug 8 (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: Sonnette 7 SW, MT (NOAA GHCN-Daily ID USC00247740), elevation 3,914 ft, 18.1 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Brandenberg, MT | 22 mi | May 18 | Sep 22 |
| Moorhead 9 NE, MT | 31 mi | May 17 | Sep 22 |
| Colstrip, MT | 35 mi | May 15 | Sep 30 |
The average last-frost dates of these stations span 10 days, a rough guide to local variation. See data sources & methods.
Frost questions for 59003
When is the last frost in 59003?
The average (50% chance) last spring freeze of 32°F for ZIP 59003 is May 25. For a more cautious planting date, use June 7, when only 1 year in 10 still sees a later freeze.
When is the first frost in 59003?
The average first fall freeze is September 19. In 1 year in 10 it comes by September 1.
What hardiness zone is 59003?
ZIP 59003 is in USDA zone 4b (-25 to -20°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 59003 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
59043 Lame Deer 59062 59012 59351 59317 Broadus 59016 Busby 59025 59323 Colstrip
Other ZIP codes in Powder River County
59062 59314 59316 59317 59343 59351 All Powder River County frost dates · Montana frost dates
Never miss a frost: get The Dial
Weekly yard timing, plus frost and soil-temperature alerts for your ZIP code.
- Freeze alerts
- Soil-temp heads-up
- Weekly yard to-dos
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.