Frost dates for ZIP 59643 (Toston, 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, Townsend 3SE, MT (13 miles away).
- Average last spring frostMay 1950% 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)122 daysmedian, 32°F threshold
- USDA hardiness zone5a-20 to -15°F avg. coldest night
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This week in your yard
As of Oct 17, 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 46°F, as of Oct 17, 10:00 PM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Table Mountain (23 mi).
4-inch depth
42°F Below 50°F
24-hour average · latest 46°F, as of Oct 17, 10:00 PM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Table Mountain (23 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 59643 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 42°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 8 |
| 50% (the "average" last frost) | May 19 |
| 10% (cautious: only 1 year in 10 freezes later) | Jun 2 |
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 5 |
| 50% (the "average" first frost) | Sep 19 |
| 90% (late: most years have frozen by now) | Oct 2 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | Jun 5 | Sep 7 |
| 32°F (freeze) | May 19 | Sep 19 |
| 28°F (hard freeze) | May 7 | Oct 1 |
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 59643
Dates count from your average last spring frost (May 19) 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 24–Apr 7 | May 26–Jun 9 (transplant) | – |
| Pepper (sweet and hot) | Mar 10–24 | Jun 2–16 (transplant) | – |
| Eggplant | Mar 10–24 | Jun 2–16 (transplant) | – |
| Tomatillo | Mar 24–Apr 7 | May 26–Jun 9 (transplant) | – |
| Lettuce | Mar 24–Apr 7 | Apr 28–May 19 (transplant) Apr 21–Jun 2 (sow outdoors) | Jul 25–Aug 15 (transplant) Jul 11–Aug 8 (sowing) |
| Spinach | – | Apr 7–28 (sow outdoors) | Jul 25–Aug 15 (sowing) |
| Kale | Mar 24–Apr 7 | Apr 21–May 5 (transplant) Apr 21–May 5 (sow outdoors) | Jun 27–Jul 25 (transplant) Jun 13–Jul 11 (sowing) |
| Collards | Mar 24–Apr 7 | Apr 21–May 19 (transplant) Apr 21–May 19 (sow outdoors) | Jun 27–Jul 25 (transplant) Jun 13–Jul 11 (sowing) |
| Broccoli | Mar 10–24 | Apr 21–May 5 (transplant) | Jun 13–Jul 11 (transplant) |
| Cabbage | Mar 10–24 | Apr 21–May 5 (transplant) | Jun 13–Jul 11 (transplant) |
| Cauliflower | Mar 10–24 | May 5–19 (transplant) | Jun 13–Jul 11 (transplant) |
| Brussels sprouts | Feb 24–Mar 10 | Apr 21–May 5 (transplant) | May 30–Jun 20 (transplant) |
| Kohlrabi | Mar 24–Apr 7 | Apr 21–May 5 (transplant) Apr 21–May 5 (sow outdoors) | Jul 11–25 (sowing) |
| Bok choy / Asian greens | – | Apr 21–May 5 (sow outdoors) | Jul 25–Aug 8 (sowing) |
| Arugula | – | Apr 21–May 19 (sow outdoors) | Jul 25–Aug 22 (sowing) |
| Mustard greens | – | Apr 21–May 12 (sow outdoors) | Jul 25–Aug 8 (sowing) |
| Swiss chard | Apr 7–21 | May 5–26 (transplant) May 5–Jun 2 (sow outdoors) | Jul 11–25 (sowing) |
| Beet | – | Apr 21–May 19 (sow outdoors) | Jul 11–25 (sowing) |
| Carrot | – | Apr 28–May 26 (sow outdoors) | Jun 27–Jul 11 (sowing) |
| Radish | – | Apr 14–May 26 (sow outdoors) | Aug 8–22 (sowing) |
| Turnip | – | Apr 21–May 12 (sow outdoors) | Jul 11–25 (sowing) |
| Parsnip | – | Apr 28–May 19 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 24–Apr 21 (sow outdoors) | Jun 27–Jul 11 (sowing) |
| Onion (bulbing) | Feb 24–Mar 10 | Apr 7–21 (transplant) | – |
| Green onion / scallion | – | Apr 7–May 5 (sow outdoors) | Jul 11–25 (sowing) |
| Leek | Feb 24–Mar 10 | Apr 21–May 5 (transplant) | – |
| Garlic | – | – | Aug 8–Sep 5 (sowing) |
| Shallot | – | Apr 7–21 (transplant) | Aug 8–Sep 5 (sowing) |
| Potato | – | Apr 21–May 5 (transplant) | May 30–Jun 13 (transplant) |
| Sweet potato | – | Jun 9–23 (transplant) | – |
| Sweet corn | – | May 26–Jun 9 (sow outdoors) | – |
| Bean, bush (snap) | – | May 26–Jun 9 (sow outdoors) | – |
| Bean, pole | – | May 26–Jun 9 (sow outdoors) | – |
| Lima bean | – | Jun 2–16 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Jun 9–30 (sow outdoors) | – |
| Cucumber | Apr 21–28 | May 26–Jun 9 (transplant) May 26–Jun 9 (sow outdoors) | – |
| Summer squash / zucchini | Apr 21–28 | May 26–Jun 9 (transplant) May 26–Jun 9 (sow outdoors) | – |
| Winter squash | Apr 21–28 | May 26–Jun 9 (transplant) May 26–Jun 9 (sow outdoors) | – |
| Pumpkin | – | May 26–Jun 9 (sow outdoors) | – |
| Watermelon | Apr 21–28 | Jun 2–16 (transplant) Jun 2–16 (sow outdoors) | – |
| Cantaloupe / muskmelon | Apr 21–28 | Jun 2–16 (transplant) Jun 2–16 (sow outdoors) | – |
| Okra | Apr 7–21 | Jun 2–16 (transplant) Jun 2–16 (sow outdoors) | – |
| Celery | Feb 24–Mar 10 | May 26–Jun 2 (transplant) | – |
| Basil | Apr 7–21 | May 26–Jun 9 (transplant) May 26–Jun 9 (sow outdoors) | – |
| Cilantro | – | May 5–Jun 2 (sow outdoors) | Jul 25–Aug 8 (sowing) |
| Parsley | Mar 10–24 | May 5–19 (transplant) Apr 28–May 19 (sow outdoors) | – |
| Dill | – | May 19–Jun 2 (sow outdoors) | Jul 25–Aug 8 (sowing) |
| Sunflower | – | May 19–Jun 2 (sow outdoors) | – |
| Asparagus (crowns) | – | Apr 21–May 5 (transplant) | – |
| Rhubarb (crowns) | – | Apr 21–May 5 (transplant) | – |
| Strawberry (plants) | – | Apr 21–May 5 (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: Townsend 3SE, MT (NOAA GHCN-Daily ID USC00248324), elevation 3,964 ft, 12.9 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Trident, MT | 14 mi | May 9 | Sep 27 |
| Logan Landfill, MT | 20 mi | May 26 | Sep 15 |
| Boulder, MT | 26 mi | Jun 7 | Sep 8 |
The average last-frost dates of these stations span 29 days, a rough guide to local variation. See data sources & methods.
Frost questions for 59643
When is the last frost in 59643?
The average (50% chance) last spring freeze of 32°F for ZIP 59643 is May 19. For a more cautious planting date, use June 2, when only 1 year in 10 still sees a later freeze.
When is the first frost in 59643?
The average first fall freeze is September 19. In 1 year in 10 it comes by September 5.
What hardiness zone is 59643?
ZIP 59643 is in USDA zone 5a (-20 to -15°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 59643 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
59752 Wheatland 59632 Elkhorn 59644 The Silos 59647 Winston 59721 Cardwell 59714 Belgrade 59760 Willow Creek 59638 Jefferson City
Other ZIP codes in Broadwater County
59644 59647 All Broadwater County frost dates · Montana frost dates
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