Fall in zone 3bPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 59544 (Whitewater, 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, Port Of Morgan, MT (18 miles away).
- Average last spring frostMay 1950% chance of a 32°F freeze after this date
- Average first fall frostSep 2250% chance of a 32°F freeze by this date
- Growing season (frost-free)124 daysmedian, 32°F threshold
- USDA hardiness zone3b-35 to -30°F avg. coldest night
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Frost and freeze alerts from the NWS forecast for 59544, the spring soil-temperature heads-up for pre-emergent, and a short weekly yard-timing email.
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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
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 59544 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 5 |
| 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 9 |
| 50% (the "average" first frost) | Sep 22 |
| 90% (late: most years have frozen by now) | Oct 4 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | May 31 | Sep 12 |
| 32°F (freeze) | May 19 | Sep 22 |
| 28°F (hard freeze) | May 8 | Sep 30 |
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 59544
Dates count from your average last spring frost (May 19) and first fall frost (Sep 22). 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 28–Aug 18 (transplant) Jul 14–Aug 11 (sowing) |
| Spinach | – | Apr 7–28 (sow outdoors) | Jul 28–Aug 18 (sowing) |
| Kale | Mar 24–Apr 7 | Apr 21–May 5 (transplant) Apr 21–May 5 (sow outdoors) | Jun 30–Jul 28 (transplant) Jun 16–Jul 14 (sowing) |
| Collards | Mar 24–Apr 7 | Apr 21–May 19 (transplant) Apr 21–May 19 (sow outdoors) | Jun 30–Jul 28 (transplant) Jun 16–Jul 14 (sowing) |
| Broccoli | Mar 10–24 | Apr 21–May 5 (transplant) | Jun 16–Jul 14 (transplant) |
| Cabbage | Mar 10–24 | Apr 21–May 5 (transplant) | Jun 16–Jul 14 (transplant) |
| Cauliflower | Mar 10–24 | May 5–19 (transplant) | Jun 16–Jul 14 (transplant) |
| Brussels sprouts | Feb 24–Mar 10 | Apr 21–May 5 (transplant) | Jun 2–23 (transplant) |
| Kohlrabi | Mar 24–Apr 7 | Apr 21–May 5 (transplant) Apr 21–May 5 (sow outdoors) | Jul 14–28 (sowing) |
| Bok choy / Asian greens | – | Apr 21–May 5 (sow outdoors) | Jul 28–Aug 11 (sowing) |
| Arugula | – | Apr 21–May 19 (sow outdoors) | Jul 28–Aug 25 (sowing) |
| Mustard greens | – | Apr 21–May 12 (sow outdoors) | Jul 28–Aug 11 (sowing) |
| Swiss chard | Apr 7–21 | May 5–26 (transplant) May 5–Jun 2 (sow outdoors) | Jul 14–28 (sowing) |
| Beet | – | Apr 21–May 19 (sow outdoors) | Jul 14–28 (sowing) |
| Carrot | – | Apr 28–May 26 (sow outdoors) | Jun 30–Jul 14 (sowing) |
| Radish | – | Apr 14–May 26 (sow outdoors) | Aug 11–25 (sowing) |
| Turnip | – | Apr 21–May 12 (sow outdoors) | Jul 14–28 (sowing) |
| Parsnip | – | Apr 28–May 19 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 24–Apr 21 (sow outdoors) | Jun 30–Jul 14 (sowing) |
| Onion (bulbing) | Feb 24–Mar 10 | Apr 7–21 (transplant) | – |
| Green onion / scallion | – | Apr 7–May 5 (sow outdoors) | Jul 14–28 (sowing) |
| Leek | Feb 24–Mar 10 | Apr 21–May 5 (transplant) | – |
| Garlic | – | – | Aug 11–Sep 8 (sowing) |
| Shallot | – | Apr 7–21 (transplant) | Aug 11–Sep 8 (sowing) |
| Potato | – | Apr 21–May 5 (transplant) | Jun 2–16 (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 28–Aug 11 (sowing) |
| Parsley | Mar 10–24 | May 5–19 (transplant) Apr 28–May 19 (sow outdoors) | – |
| Dill | – | May 19–Jun 2 (sow outdoors) | Jul 28–Aug 11 (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 14–Aug 11 (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: Port Of Morgan, MT (NOAA GHCN-Daily ID USC00246672), elevation 2,830 ft, 18.5 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Saco 1 NNW, MT | 25 mi | May 15 | Sep 23 |
| Malta 7 E, MT | 29 mi | May 7 | Sep 28 |
| Malta, MT | 34 mi | May 10 | Sep 29 |
The average last-frost dates of these stations span 12 days, a rough guide to local variation. See data sources & methods.
Frost questions for 59544
When is the last frost in 59544?
The average (50% chance) last spring freeze of 32°F for ZIP 59544 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 59544?
The average first fall freeze is September 22. In 1 year in 10 it comes by September 9.
What hardiness zone is 59544?
ZIP 59544 is in USDA zone 3b (-35 to -30°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 59544 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
59537 Loring Colony 59261 Saco 59241 Hinsdale 59542 Turner Colony 59250 Opheim 59273 59529 Hogeland 59231 St. Marie
Other ZIP codes in Phillips County
59261 59524 59537 59538 59546 All Phillips 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
- 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.