Fall in zone 4bPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 59418 (Judith Basin County, 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, Judith Gap, MT (10 miles away).
- Average last spring frostJun 150% chance of a 32°F freeze after this date
- Average first fall frostSep 1550% chance of a 32°F freeze by this date
- Growing season (frost-free)104 daysmedian, 32°F threshold
- USDA hardiness zone4b-25 to -20°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
43°F Below 50°F
24-hour average · latest 43°F, as of Oct 18, 2:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Moccasin (18 mi), Lewistown 42 WSW (21 mi).
4-inch depth
43°F Below 50°F
24-hour average · latest 44°F, as of Oct 18, 2:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Moccasin (18 mi), Lewistown 42 WSW (21 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 59418 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 17 |
| 50% (the "average" last frost) | Jun 1 |
| 10% (cautious: only 1 year in 10 freezes later) | Jun 16 |
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) | Aug 31 |
| 50% (the "average" first frost) | Sep 15 |
| 90% (late: most years have frozen by now) | Sep 28 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | n/a | n/a |
| 32°F (freeze) | Jun 1 | Sep 15 |
| 28°F (hard freeze) | May 15 | Sep 28 |
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 59418
Dates count from your average last spring frost (Jun 1) and first fall frost (Sep 15). 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 | Apr 6–20 | Jun 8–22 (transplant) | – |
| Pepper (sweet and hot) | Mar 23–Apr 6 | Jun 15–29 (transplant) | – |
| Eggplant | Mar 23–Apr 6 | Jun 15–29 (transplant) | – |
| Tomatillo | Apr 6–20 | Jun 8–22 (transplant) | – |
| Lettuce | Apr 6–20 | May 11–Jun 1 (transplant) May 4–Jun 15 (sow outdoors) | Jul 21–Aug 11 (transplant) Jul 7–Aug 4 (sowing) |
| Spinach | – | Apr 20–May 11 (sow outdoors) | Jul 21–Aug 11 (sowing) |
| Kale | Apr 6–20 | May 4–18 (transplant) May 4–18 (sow outdoors) | Jun 23–Jul 21 (transplant) Jun 9–Jul 7 (sowing) |
| Collards | Apr 6–20 | May 4–Jun 1 (transplant) May 4–Jun 1 (sow outdoors) | Jun 23–Jul 21 (transplant) Jun 9–Jul 7 (sowing) |
| Broccoli | Mar 23–Apr 6 | May 4–18 (transplant) | Jun 9–Jul 7 (transplant) |
| Cabbage | Mar 23–Apr 6 | May 4–18 (transplant) | Jun 9–Jul 7 (transplant) |
| Cauliflower | Mar 23–Apr 6 | May 18–Jun 1 (transplant) | Jun 9–Jul 7 (transplant) |
| Brussels sprouts | Mar 9–23 | May 4–18 (transplant) | May 26–Jun 16 (transplant) |
| Kohlrabi | Apr 6–20 | May 4–18 (transplant) May 4–18 (sow outdoors) | Jul 7–21 (sowing) |
| Bok choy / Asian greens | – | May 4–18 (sow outdoors) | Jul 21–Aug 4 (sowing) |
| Arugula | – | May 4–Jun 1 (sow outdoors) | Jul 21–Aug 18 (sowing) |
| Mustard greens | – | May 4–25 (sow outdoors) | Jul 21–Aug 4 (sowing) |
| Swiss chard | Apr 20–May 4 | May 18–Jun 8 (transplant) May 18–Jun 15 (sow outdoors) | Jul 7–21 (sowing) |
| Beet | – | May 4–Jun 1 (sow outdoors) | Jul 7–21 (sowing) |
| Carrot | – | May 11–Jun 8 (sow outdoors) | Jun 23–Jul 7 (sowing) |
| Radish | – | Apr 27–Jun 8 (sow outdoors) | Aug 4–18 (sowing) |
| Turnip | – | May 4–25 (sow outdoors) | Jul 7–21 (sowing) |
| Parsnip | – | May 11–Jun 1 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Apr 6–May 4 (sow outdoors) | Jun 23–Jul 7 (sowing) |
| Onion (bulbing) | Mar 9–23 | Apr 20–May 4 (transplant) | – |
| Green onion / scallion | – | Apr 20–May 18 (sow outdoors) | Jul 7–21 (sowing) |
| Leek | Mar 9–23 | May 4–18 (transplant) | – |
| Garlic | – | – | Aug 4–Sep 1 (sowing) |
| Shallot | – | Apr 20–May 4 (transplant) | Aug 4–Sep 1 (sowing) |
| Potato | – | May 4–18 (transplant) | May 26–Jun 9 (transplant) |
| Sweet potato | – | Jun 22–Jul 6 (transplant) | – |
| Sweet corn | – | Jun 8–22 (sow outdoors) | – |
| Bean, bush (snap) | – | Jun 8–22 (sow outdoors) | – |
| Bean, pole | – | Jun 8–22 (sow outdoors) | – |
| Lima bean | – | Jun 15–29 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Jun 22–Jul 13 (sow outdoors) | – |
| Cucumber | May 4–11 | Jun 8–22 (transplant) Jun 8–22 (sow outdoors) | – |
| Summer squash / zucchini | May 4–11 | Jun 8–22 (transplant) Jun 8–22 (sow outdoors) | – |
| Winter squash | May 4–11 | Jun 8–22 (transplant) Jun 8–22 (sow outdoors) | – |
| Pumpkin | – | Jun 8–22 (sow outdoors) | – |
| Watermelon | May 4–11 | Jun 15–29 (transplant) Jun 15–29 (sow outdoors) | – |
| Cantaloupe / muskmelon | May 4–11 | Jun 15–29 (transplant) Jun 15–29 (sow outdoors) | – |
| Okra | Apr 20–May 4 | Jun 15–29 (transplant) Jun 15–29 (sow outdoors) | – |
| Celery | Mar 9–23 | Jun 8–15 (transplant) | – |
| Basil | Apr 20–May 4 | Jun 8–22 (transplant) Jun 8–22 (sow outdoors) | – |
| Cilantro | – | May 18–Jun 15 (sow outdoors) | Jul 21–Aug 4 (sowing) |
| Parsley | Mar 23–Apr 6 | May 18–Jun 1 (transplant) May 11–Jun 1 (sow outdoors) | – |
| Dill | – | Jun 1–15 (sow outdoors) | Jul 21–Aug 4 (sowing) |
| Sunflower | – | Jun 1–15 (sow outdoors) | – |
| Asparagus (crowns) | – | May 4–18 (transplant) | – |
| Rhubarb (crowns) | – | May 4–18 (transplant) | – |
| Strawberry (plants) | – | May 4–18 (transplant) | Jul 7–Aug 4 (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: Judith Gap, MT (NOAA GHCN-Daily ID USC00244538), elevation 4,630 ft, 10.0 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Harlowton 11NW, MT | 16 mi | May 30 | Sep 20 |
| Moccasin EXP STN, MT | 18 mi | May 28 | Sep 20 |
| Lewistown 42 WSW, MT | 21 mi | Jun 15 | Sep 4 |
The average last-frost dates of these stations span 18 days, a rough guide to local variation. See data sources & methods.
Frost questions for 59418
When is the last frost in 59418?
The average (50% chance) last spring freeze of 32°F for ZIP 59418 is June 1. For a more cautious planting date, use June 16, when only 1 year in 10 still sees a later freeze.
When is the first frost in 59418?
The average first fall freeze is September 15. In 1 year in 10 it comes by August 31.
What hardiness zone is 59418?
ZIP 59418 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 59418 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
59452 Sapphire Ridge 59464 Moore 59453 Judith Gap 59462 Moccasin 59036 Harlowton 59479 Stanford 59078 Shawmut 59457 Lewistown
Other ZIP codes in Judith Basin County
59447 59452 59462 59469 59479 All Judith Basin County frost dates · Montana frost dates
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Weekly yard timing, plus frost and soil-temperature alerts for your ZIP code.
- Freeze alerts
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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.