Frost dates for ZIP 59078 (Shawmut, 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, Ryegate 18 NNW, MT (10 miles away).
- Average last spring frostMay 2650% chance of a 32°F freeze after this date
- Average first fall frostSep 1850% chance of a 32°F freeze by this date
- Growing season (frost-free)112 daysmedian, 32°F threshold
- USDA hardiness zone4b-25 to -20°F avg. coldest night
This week in your yard
As of Oct 18, 2026, from your frost dates, zone and soil temperature. Lawn timing · Vegetables · Pruning · Plants
Fall in zone 4b
Soil temperature now
2-inch depth
43°F Below 50°F
24-hour average · latest 40°F, as of Oct 18, 8:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Moccasin (49 mi), Lewistown 42 WSW (49 mi).
4-inch depth
43°F Below 50°F
24-hour average · latest 42°F, as of Oct 18, 8:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Moccasin (49 mi), Lewistown 42 WSW (49 mi).
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 59078 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 43°F at 4 inches (estimated soil temperature, not a station reading). Fall pre-emergent window is mostly past. Next: spring, when soil reaches 50°F (typically 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 26 |
| 10% (cautious: only 1 year in 10 freezes later) | Jun 13 |
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 18 |
| 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 13 | Sep 6 |
| 32°F (freeze) | May 26 | Sep 18 |
| 28°F (hard freeze) | May 11 | 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 59078
Dates count from your average last spring frost (May 26) and first fall frost (Sep 18). 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 31–Apr 14 | Jun 2–16 (transplant) | – |
| Pepper (sweet and hot) | Mar 17–31 | Jun 9–23 (transplant) | – |
| Eggplant | Mar 17–31 | Jun 9–23 (transplant) | – |
| Tomatillo | Mar 31–Apr 14 | Jun 2–16 (transplant) | – |
| Lettuce | Mar 31–Apr 14 | May 5–26 (transplant) Apr 28–Jun 9 (sow outdoors) | Jul 24–Aug 14 (transplant) Jul 10–Aug 7 (sowing) |
| Spinach | – | Apr 14–May 5 (sow outdoors) | Jul 24–Aug 14 (sowing) |
| Kale | Mar 31–Apr 14 | Apr 28–May 12 (transplant) Apr 28–May 12 (sow outdoors) | Jun 26–Jul 24 (transplant) Jun 12–Jul 10 (sowing) |
| Collards | Mar 31–Apr 14 | Apr 28–May 26 (transplant) Apr 28–May 26 (sow outdoors) | Jun 26–Jul 24 (transplant) Jun 12–Jul 10 (sowing) |
| Broccoli | Mar 17–31 | Apr 28–May 12 (transplant) | Jun 12–Jul 10 (transplant) |
| Cabbage | Mar 17–31 | Apr 28–May 12 (transplant) | Jun 12–Jul 10 (transplant) |
| Cauliflower | Mar 17–31 | May 12–26 (transplant) | Jun 12–Jul 10 (transplant) |
| Brussels sprouts | Mar 3–17 | Apr 28–May 12 (transplant) | May 29–Jun 19 (transplant) |
| Kohlrabi | Mar 31–Apr 14 | Apr 28–May 12 (transplant) Apr 28–May 12 (sow outdoors) | Jul 10–24 (sowing) |
| Bok choy / Asian greens | – | Apr 28–May 12 (sow outdoors) | Jul 24–Aug 7 (sowing) |
| Arugula | – | Apr 28–May 26 (sow outdoors) | Jul 24–Aug 21 (sowing) |
| Mustard greens | – | Apr 28–May 19 (sow outdoors) | Jul 24–Aug 7 (sowing) |
| Swiss chard | Apr 14–28 | May 12–Jun 2 (transplant) May 12–Jun 9 (sow outdoors) | Jul 10–24 (sowing) |
| Beet | – | Apr 28–May 26 (sow outdoors) | Jul 10–24 (sowing) |
| Carrot | – | May 5–Jun 2 (sow outdoors) | Jun 26–Jul 10 (sowing) |
| Radish | – | Apr 21–Jun 2 (sow outdoors) | Aug 7–21 (sowing) |
| Turnip | – | Apr 28–May 19 (sow outdoors) | Jul 10–24 (sowing) |
| Parsnip | – | May 5–26 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 31–Apr 28 (sow outdoors) | Jun 26–Jul 10 (sowing) |
| Onion (bulbing) | Mar 3–17 | Apr 14–28 (transplant) | – |
| Green onion / scallion | – | Apr 14–May 12 (sow outdoors) | Jul 10–24 (sowing) |
| Leek | Mar 3–17 | Apr 28–May 12 (transplant) | – |
| Garlic | – | – | Aug 7–Sep 4 (sowing) |
| Shallot | – | Apr 14–28 (transplant) | Aug 7–Sep 4 (sowing) |
| Potato | – | Apr 28–May 12 (transplant) | May 29–Jun 12 (transplant) |
| Sweet potato | – | Jun 16–30 (transplant) | – |
| Sweet corn | – | Jun 2–16 (sow outdoors) | – |
| Bean, bush (snap) | – | Jun 2–16 (sow outdoors) | – |
| Bean, pole | – | Jun 2–16 (sow outdoors) | – |
| Lima bean | – | Jun 9–23 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Jun 16–Jul 7 (sow outdoors) | – |
| Cucumber | Apr 28–May 5 | Jun 2–16 (transplant) Jun 2–16 (sow outdoors) | – |
| Summer squash / zucchini | Apr 28–May 5 | Jun 2–16 (transplant) Jun 2–16 (sow outdoors) | – |
| Winter squash | Apr 28–May 5 | Jun 2–16 (transplant) Jun 2–16 (sow outdoors) | – |
| Pumpkin | – | Jun 2–16 (sow outdoors) | – |
| Watermelon | Apr 28–May 5 | Jun 9–23 (transplant) Jun 9–23 (sow outdoors) | – |
| Cantaloupe / muskmelon | Apr 28–May 5 | Jun 9–23 (transplant) Jun 9–23 (sow outdoors) | – |
| Okra | Apr 14–28 | Jun 9–23 (transplant) Jun 9–23 (sow outdoors) | – |
| Celery | Mar 3–17 | Jun 2–9 (transplant) | – |
| Basil | Apr 14–28 | Jun 2–16 (transplant) Jun 2–16 (sow outdoors) | – |
| Cilantro | – | May 12–Jun 9 (sow outdoors) | Jul 24–Aug 7 (sowing) |
| Parsley | Mar 17–31 | May 12–26 (transplant) May 5–26 (sow outdoors) | – |
| Dill | – | May 26–Jun 9 (sow outdoors) | Jul 24–Aug 7 (sowing) |
| Sunflower | – | May 26–Jun 9 (sow outdoors) | – |
| Asparagus (crowns) | – | Apr 28–May 12 (transplant) | – |
| Rhubarb (crowns) | – | Apr 28–May 12 (transplant) | – |
| Strawberry (plants) | – | Apr 28–May 12 (transplant) | Jul 10–Aug 7 (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: Ryegate 18 NNW, MT (NOAA GHCN-Daily ID USC00247263), elevation 4,440 ft, 10.3 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Judith Gap 13 E, MT | 13 mi | Jun 3 | Sep 15 |
| Ryegate, MT | 14 mi | May 17 | Sep 23 |
| Harlowton, MT | 17 mi | May 23 | Sep 16 |
The average last-frost dates of these stations span 17 days, a rough guide to local variation. See data sources & methods.
Frost questions for 59078
When is the last frost in 59078?
The average (50% chance) last spring freeze of 32°F for ZIP 59078 is May 26. For a more cautious planting date, use June 13, when only 1 year in 10 still sees a later freeze.
When is the first frost in 59078?
The average first fall freeze is September 18. In 1 year in 10 it comes by September 1.
What hardiness zone is 59078?
ZIP 59078 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 59078 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
59074 Ryegate 59453 Judith Gap 59036 Harlowton 59046 Lavina 59055 59464 Moore 59418 59067 Rapelje
Other ZIP codes in Wheatland County
59036 59085 59453 All Wheatland County frost dates · Montana frost dates
Get The Dial for 59078 (Shawmut)
Frost and freeze alerts from the NWS forecast for 59078, 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.