Frost dates for ZIP 51249 (Sibley, IA)
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, Sibley, IA (1 miles away).
- Average last spring frostMay 550% chance of a 32°F freeze after this date
- Average first fall frostOct 350% chance of a 32°F freeze by this date
- Growing season (frost-free)152 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 17, 2026, from your frost dates, zone and soil temperature. Lawn timing · Vegetables · Pruning · Plants
Soil temperature now
2-inch depth
49°F Below 50°F
24-hour average · latest 51°F, as of Oct 17, 10:00 PM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Sioux Falls 14 NNE (50 mi), Eros Data Center (50 mi).
4-inch depth
51°F 50–55°F
24-hour average · latest 52°F, as of Oct 17, 10:00 PM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Sioux Falls 14 NNE (50 mi), Eros Data Center (50 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 51249 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 51°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 early May).
Fertilizer window
Lawn region: North (cool-season). 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) | Apr 22 |
| 50% (the "average" last frost) | May 5 |
| 10% (cautious: only 1 year in 10 freezes later) | May 17 |
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 21 |
| 50% (the "average" first frost) | Oct 3 |
| 90% (late: most years have frozen by now) | Oct 17 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | May 12 | Sep 27 |
| 32°F (freeze) | May 5 | Oct 3 |
| 28°F (hard freeze) | Apr 25 | Oct 13 |
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 51249
Dates count from your average last spring frost (May 5) and first fall frost (Oct 3). 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 10–24 | May 12–26 (transplant) | – |
| Pepper (sweet and hot) | Feb 24–Mar 10 | May 19–Jun 2 (transplant) | – |
| Eggplant | Feb 24–Mar 10 | May 19–Jun 2 (transplant) | – |
| Tomatillo | Mar 10–24 | May 12–26 (transplant) | – |
| Lettuce | Mar 10–24 | Apr 14–May 5 (transplant) Apr 7–May 19 (sow outdoors) | Aug 8–29 (transplant) Jul 25–Aug 22 (sowing) |
| Spinach | – | Mar 24–Apr 14 (sow outdoors) | Aug 8–29 (sowing) |
| Kale | Mar 10–24 | Apr 7–21 (transplant) Apr 7–21 (sow outdoors) | Jul 11–Aug 8 (transplant) Jun 27–Jul 25 (sowing) |
| Collards | Mar 10–24 | Apr 7–May 5 (transplant) Apr 7–May 5 (sow outdoors) | Jul 11–Aug 8 (transplant) Jun 27–Jul 25 (sowing) |
| Broccoli | Feb 24–Mar 10 | Apr 7–21 (transplant) | Jun 27–Jul 25 (transplant) |
| Cabbage | Feb 24–Mar 10 | Apr 7–21 (transplant) | Jun 27–Jul 25 (transplant) |
| Cauliflower | Feb 24–Mar 10 | Apr 21–May 5 (transplant) | Jun 27–Jul 25 (transplant) |
| Brussels sprouts | Feb 10–24 | Apr 7–21 (transplant) | Jun 13–Jul 4 (transplant) |
| Kohlrabi | Mar 10–24 | Apr 7–21 (transplant) Apr 7–21 (sow outdoors) | Jul 25–Aug 8 (sowing) |
| Bok choy / Asian greens | – | Apr 7–21 (sow outdoors) | Aug 8–22 (sowing) |
| Arugula | – | Apr 7–May 5 (sow outdoors) | Aug 8–Sep 5 (sowing) |
| Mustard greens | – | Apr 7–28 (sow outdoors) | Aug 8–22 (sowing) |
| Swiss chard | Mar 24–Apr 7 | Apr 21–May 12 (transplant) Apr 21–May 19 (sow outdoors) | Jul 25–Aug 8 (sowing) |
| Beet | – | Apr 7–May 5 (sow outdoors) | Jul 25–Aug 8 (sowing) |
| Carrot | – | Apr 14–May 12 (sow outdoors) | Jul 11–25 (sowing) |
| Radish | – | Mar 31–May 12 (sow outdoors) | Aug 22–Sep 5 (sowing) |
| Turnip | – | Apr 7–28 (sow outdoors) | Jul 25–Aug 8 (sowing) |
| Parsnip | – | Apr 14–May 5 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 10–Apr 7 (sow outdoors) | Jul 11–25 (sowing) |
| Onion (bulbing) | Feb 10–24 | Mar 24–Apr 7 (transplant) | – |
| Green onion / scallion | – | Mar 24–Apr 21 (sow outdoors) | Jul 25–Aug 8 (sowing) |
| Leek | Feb 10–24 | Apr 7–21 (transplant) | – |
| Garlic | – | – | Aug 22–Sep 19 (sowing) |
| Shallot | – | Mar 24–Apr 7 (transplant) | Aug 22–Sep 19 (sowing) |
| Potato | – | Apr 7–21 (transplant) | Jun 13–27 (transplant) |
| Sweet potato | – | May 26–Jun 9 (transplant) | – |
| Sweet corn | – | May 12–26 (sow outdoors) | – |
| Bean, bush (snap) | – | May 12–26 (sow outdoors) | – |
| Bean, pole | – | May 12–26 (sow outdoors) | – |
| Lima bean | – | May 19–Jun 2 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 26–Jun 16 (sow outdoors) | – |
| Cucumber | Apr 7–14 | May 12–26 (transplant) May 12–26 (sow outdoors) | – |
| Summer squash / zucchini | Apr 7–14 | May 12–26 (transplant) May 12–26 (sow outdoors) | – |
| Winter squash | Apr 7–14 | May 12–26 (transplant) May 12–26 (sow outdoors) | – |
| Pumpkin | – | May 12–26 (sow outdoors) | – |
| Watermelon | Apr 7–14 | May 19–Jun 2 (transplant) May 19–Jun 2 (sow outdoors) | – |
| Cantaloupe / muskmelon | Apr 7–14 | May 19–Jun 2 (transplant) May 19–Jun 2 (sow outdoors) | – |
| Okra | Mar 24–Apr 7 | May 19–Jun 2 (transplant) May 19–Jun 2 (sow outdoors) | – |
| Celery | Feb 10–24 | May 12–19 (transplant) | – |
| Basil | Mar 24–Apr 7 | May 12–26 (transplant) May 12–26 (sow outdoors) | – |
| Cilantro | – | Apr 21–May 19 (sow outdoors) | Aug 8–22 (sowing) |
| Parsley | Feb 24–Mar 10 | Apr 21–May 5 (transplant) Apr 14–May 5 (sow outdoors) | – |
| Dill | – | May 5–19 (sow outdoors) | Aug 8–22 (sowing) |
| Sunflower | – | May 5–19 (sow outdoors) | – |
| Asparagus (crowns) | – | Apr 7–21 (transplant) | – |
| Rhubarb (crowns) | – | Apr 7–21 (transplant) | – |
| Strawberry (plants) | – | Apr 7–21 (transplant) | Jul 25–Aug 22 (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: Sibley, IA (NOAA GHCN-Daily ID USC00137664), elevation 1,529 ft, 0.9 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Sanborn, IA | 16 mi | May 1 | Oct 7 |
| Sheldon, IA | 17 mi | May 5 | Sep 28 |
| Worthington 2 NNE, MN | 18 mi | May 3 | Oct 4 |
The average last-frost dates of these stations span 4 days, a rough guide to local variation. See data sources & methods.
Frost questions for 51249
When is the last frost in 51249?
The average (50% chance) last spring freeze of 32°F for ZIP 51249 is May 5. For a more cautious planting date, use May 17, when only 1 year in 10 still sees a later freeze.
When is the first frost in 51249?
The average first fall freeze is October 3. In 1 year in 10 it comes by September 21.
What hardiness zone is 51249?
ZIP 51249 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 51249 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
56117 Bigelow 51243 Little Rock 51232 Ashton 51354 Ocheyedan 51350 Melvin 56168 Rushmore 51237 George 51248 Sanborn
Other ZIP codes in Osceola County
51232 51345 51350 51354 All Osceola County frost dates · Iowa frost dates
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