Frost dates for ZIP 59531 (Joplin, 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, Rudyard 21 N, MT (10 miles away).
- Average last spring frostMay 3050% chance of a 32°F freeze after this date
- Average first fall frostSep 1150% chance of a 32°F freeze by this date
- Growing season (frost-free)103 daysmedian, 32°F threshold
- USDA hardiness zone4a-30 to -25°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 4a
Soil temperature now
2-inch depth
48°F Below 50°F
24-hour average · latest 43°F, as of Oct 18, 8:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Violett (30 mi), Fort Assiniboine #1 (50 mi), Conrad Ag Rc (61 mi).
4-inch depth
47°F Below 50°F
24-hour average · latest 46°F, as of Oct 18, 8:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Violett (30 mi), Fort Assiniboine #1 (50 mi), Conrad Ag Rc (61 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 59531 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 47°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) | May 30 |
| 10% (cautious: only 1 year in 10 freezes later) | Jun 15 |
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 27 |
| 50% (the "average" first frost) | Sep 11 |
| 90% (late: most years have frozen by now) | Sep 24 |
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) | May 30 | Sep 11 |
| 28°F (hard freeze) | May 16 | Sep 23 |
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 59531
Dates count from your average last spring frost (May 30) and first fall frost (Sep 11). 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 4–18 | Jun 6–20 (transplant) | – |
| Pepper (sweet and hot) | Mar 21–Apr 4 | Jun 13–27 (transplant) | – |
| Eggplant | Mar 21–Apr 4 | Jun 13–27 (transplant) | – |
| Tomatillo | Apr 4–18 | Jun 6–20 (transplant) | – |
| Lettuce | Apr 4–18 | May 9–30 (transplant) May 2–Jun 13 (sow outdoors) | Jul 17–Aug 7 (transplant) Jul 3–31 (sowing) |
| Spinach | – | Apr 18–May 9 (sow outdoors) | Jul 17–Aug 7 (sowing) |
| Kale | Apr 4–18 | May 2–16 (transplant) May 2–16 (sow outdoors) | Jun 19–Jul 17 (transplant) Jun 5–Jul 3 (sowing) |
| Collards | Apr 4–18 | May 2–30 (transplant) May 2–30 (sow outdoors) | Jun 19–Jul 17 (transplant) Jun 5–Jul 3 (sowing) |
| Broccoli | Mar 21–Apr 4 | May 2–16 (transplant) | Jun 5–Jul 3 (transplant) |
| Cabbage | Mar 21–Apr 4 | May 2–16 (transplant) | Jun 5–Jul 3 (transplant) |
| Cauliflower | Mar 21–Apr 4 | May 16–30 (transplant) | Jun 5–Jul 3 (transplant) |
| Brussels sprouts | Mar 7–21 | May 2–16 (transplant) | May 22–Jun 12 (transplant) |
| Kohlrabi | Apr 4–18 | May 2–16 (transplant) May 2–16 (sow outdoors) | Jul 3–17 (sowing) |
| Bok choy / Asian greens | – | May 2–16 (sow outdoors) | Jul 17–31 (sowing) |
| Arugula | – | May 2–30 (sow outdoors) | Jul 17–Aug 14 (sowing) |
| Mustard greens | – | May 2–23 (sow outdoors) | Jul 17–31 (sowing) |
| Swiss chard | Apr 18–May 2 | May 16–Jun 6 (transplant) May 16–Jun 13 (sow outdoors) | Jul 3–17 (sowing) |
| Beet | – | May 2–30 (sow outdoors) | Jul 3–17 (sowing) |
| Carrot | – | May 9–Jun 6 (sow outdoors) | Jun 19–Jul 3 (sowing) |
| Radish | – | Apr 25–Jun 6 (sow outdoors) | Jul 31–Aug 14 (sowing) |
| Turnip | – | May 2–23 (sow outdoors) | Jul 3–17 (sowing) |
| Parsnip | – | May 9–30 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Apr 4–May 2 (sow outdoors) | Jun 19–Jul 3 (sowing) |
| Onion (bulbing) | Mar 7–21 | Apr 18–May 2 (transplant) | – |
| Green onion / scallion | – | Apr 18–May 16 (sow outdoors) | Jul 3–17 (sowing) |
| Leek | Mar 7–21 | May 2–16 (transplant) | – |
| Garlic | – | – | Jul 31–Aug 28 (sowing) |
| Shallot | – | Apr 18–May 2 (transplant) | Jul 31–Aug 28 (sowing) |
| Potato | – | May 2–16 (transplant) | May 22–Jun 5 (transplant) |
| Sweet potato | – | Jun 20–Jul 4 (transplant) | – |
| Sweet corn | – | Jun 6–20 (sow outdoors) | – |
| Bean, bush (snap) | – | Jun 6–20 (sow outdoors) | – |
| Bean, pole | – | Jun 6–20 (sow outdoors) | – |
| Lima bean | – | Jun 13–27 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Jun 20–Jul 11 (sow outdoors) | – |
| Cucumber | May 2–9 | Jun 6–20 (transplant) Jun 6–20 (sow outdoors) | – |
| Summer squash / zucchini | May 2–9 | Jun 6–20 (transplant) Jun 6–20 (sow outdoors) | – |
| Winter squash | May 2–9 | Jun 6–20 (transplant) Jun 6–20 (sow outdoors) | – |
| Pumpkin | – | Jun 6–20 (sow outdoors) | – |
| Watermelon | May 2–9 | Jun 13–27 (transplant) Jun 13–27 (sow outdoors) | – |
| Cantaloupe / muskmelon | May 2–9 | Jun 13–27 (transplant) Jun 13–27 (sow outdoors) | – |
| Okra | Apr 18–May 2 | Jun 13–27 (transplant) Jun 13–27 (sow outdoors) | – |
| Celery | Mar 7–21 | Jun 6–13 (transplant) | – |
| Basil | Apr 18–May 2 | Jun 6–20 (transplant) Jun 6–20 (sow outdoors) | – |
| Cilantro | – | May 16–Jun 13 (sow outdoors) | Jul 17–31 (sowing) |
| Parsley | Mar 21–Apr 4 | May 16–30 (transplant) May 9–30 (sow outdoors) | – |
| Dill | – | May 30–Jun 13 (sow outdoors) | Jul 17–31 (sowing) |
| Sunflower | – | May 30–Jun 13 (sow outdoors) | – |
| Asparagus (crowns) | – | May 2–16 (transplant) | – |
| Rhubarb (crowns) | – | May 2–16 (transplant) | – |
| Strawberry (plants) | – | May 2–16 (transplant) | Jul 3–31 (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: Rudyard 21 N, MT (NOAA GHCN-Daily ID USC00247248), elevation 3,000 ft, 10.4 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Joplin, MT | 15 mi | May 21 | Sep 19 |
| Chester, MT | 20 mi | May 24 | Sep 17 |
| Gildford, MT | 27 mi | May 24 | Sep 15 |
The average last-frost dates of these stations span 9 days, a rough guide to local variation. See data sources & methods.
Frost questions for 59531
When is the last frost in 59531?
The average (50% chance) last spring freeze of 32°F for ZIP 59531 is May 30. For a more cautious planting date, use June 15, when only 1 year in 10 still sees a later freeze.
When is the first frost in 59531?
The average first fall freeze is September 11. In 1 year in 10 it comes by August 27.
What hardiness zone is 59531?
ZIP 59531 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 59531 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
59530 Inverness 59540 Rudyard 59522 Riverview Colony 59528 Hingham 59545 Whitlash 59525 Gildford 59444 Eagle Creek Colony 59461
Other ZIP codes in Liberty County
59456 59461 59522 59545 All Liberty County frost dates · Montana frost dates
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