Fall in zone 5aPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 51237 (George, 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, Rock Rapids, IA (11 miles away).
- Average last spring frostMay 150% chance of a 32°F freeze after this date
- Average first fall frostOct 450% chance of a 32°F freeze by this date
- Growing season (frost-free)156 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 18, 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 50°F, as of Oct 18, 2:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Sioux Falls 14 NNE (41 mi), Eros Data Center (41 mi).
4-inch depth
51°F 50–55°F
24-hour average · latest 52°F, as of Oct 18, 2:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Sioux Falls 14 NNE (41 mi), Eros Data Center (41 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 51237 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 18 |
| 50% (the "average" last frost) | May 1 |
| 10% (cautious: only 1 year in 10 freezes later) | May 13 |
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 4 |
| 90% (late: most years have frozen by now) | Oct 19 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | May 10 | Sep 27 |
| 32°F (freeze) | May 1 | Oct 4 |
| 28°F (hard freeze) | Apr 21 | Oct 16 |
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 51237
Dates count from your average last spring frost (May 1) and first fall frost (Oct 4). 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 6–20 | May 8–22 (transplant) | – |
| Pepper (sweet and hot) | Feb 20–Mar 6 | May 15–29 (transplant) | – |
| Eggplant | Feb 20–Mar 6 | May 15–29 (transplant) | – |
| Tomatillo | Mar 6–20 | May 8–22 (transplant) | – |
| Lettuce | Mar 6–20 | Apr 10–May 1 (transplant) Apr 3–May 15 (sow outdoors) | Aug 9–30 (transplant) Jul 26–Aug 23 (sowing) |
| Spinach | – | Mar 20–Apr 10 (sow outdoors) | Aug 9–30 (sowing) |
| Kale | Mar 6–20 | Apr 3–17 (transplant) Apr 3–17 (sow outdoors) | Jul 12–Aug 9 (transplant) Jun 28–Jul 26 (sowing) |
| Collards | Mar 6–20 | Apr 3–May 1 (transplant) Apr 3–May 1 (sow outdoors) | Jul 12–Aug 9 (transplant) Jun 28–Jul 26 (sowing) |
| Broccoli | Feb 20–Mar 6 | Apr 3–17 (transplant) | Jun 28–Jul 26 (transplant) |
| Cabbage | Feb 20–Mar 6 | Apr 3–17 (transplant) | Jun 28–Jul 26 (transplant) |
| Cauliflower | Feb 20–Mar 6 | Apr 17–May 1 (transplant) | Jun 28–Jul 26 (transplant) |
| Brussels sprouts | Feb 6–20 | Apr 3–17 (transplant) | Jun 14–Jul 5 (transplant) |
| Kohlrabi | Mar 6–20 | Apr 3–17 (transplant) Apr 3–17 (sow outdoors) | Jul 26–Aug 9 (sowing) |
| Bok choy / Asian greens | – | Apr 3–17 (sow outdoors) | Aug 9–23 (sowing) |
| Arugula | – | Apr 3–May 1 (sow outdoors) | Aug 9–Sep 6 (sowing) |
| Mustard greens | – | Apr 3–24 (sow outdoors) | Aug 9–23 (sowing) |
| Swiss chard | Mar 20–Apr 3 | Apr 17–May 8 (transplant) Apr 17–May 15 (sow outdoors) | Jul 26–Aug 9 (sowing) |
| Beet | – | Apr 3–May 1 (sow outdoors) | Jul 26–Aug 9 (sowing) |
| Carrot | – | Apr 10–May 8 (sow outdoors) | Jul 12–26 (sowing) |
| Radish | – | Mar 27–May 8 (sow outdoors) | Aug 23–Sep 6 (sowing) |
| Turnip | – | Apr 3–24 (sow outdoors) | Jul 26–Aug 9 (sowing) |
| Parsnip | – | Apr 10–May 1 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 6–Apr 3 (sow outdoors) | Jul 12–26 (sowing) |
| Onion (bulbing) | Feb 6–20 | Mar 20–Apr 3 (transplant) | – |
| Green onion / scallion | – | Mar 20–Apr 17 (sow outdoors) | Jul 26–Aug 9 (sowing) |
| Leek | Feb 6–20 | Apr 3–17 (transplant) | – |
| Garlic | – | – | Aug 23–Sep 20 (sowing) |
| Shallot | – | Mar 20–Apr 3 (transplant) | Aug 23–Sep 20 (sowing) |
| Potato | – | Apr 3–17 (transplant) | Jun 14–28 (transplant) |
| Sweet potato | – | May 22–Jun 5 (transplant) | – |
| Sweet corn | – | May 8–22 (sow outdoors) | – |
| Bean, bush (snap) | – | May 8–22 (sow outdoors) | – |
| Bean, pole | – | May 8–22 (sow outdoors) | – |
| Lima bean | – | May 15–29 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 22–Jun 12 (sow outdoors) | – |
| Cucumber | Apr 3–10 | May 8–22 (transplant) May 8–22 (sow outdoors) | – |
| Summer squash / zucchini | Apr 3–10 | May 8–22 (transplant) May 8–22 (sow outdoors) | – |
| Winter squash | Apr 3–10 | May 8–22 (transplant) May 8–22 (sow outdoors) | – |
| Pumpkin | – | May 8–22 (sow outdoors) | – |
| Watermelon | Apr 3–10 | May 15–29 (transplant) May 15–29 (sow outdoors) | – |
| Cantaloupe / muskmelon | Apr 3–10 | May 15–29 (transplant) May 15–29 (sow outdoors) | – |
| Okra | Mar 20–Apr 3 | May 15–29 (transplant) May 15–29 (sow outdoors) | – |
| Celery | Feb 6–20 | May 8–15 (transplant) | – |
| Basil | Mar 20–Apr 3 | May 8–22 (transplant) May 8–22 (sow outdoors) | – |
| Cilantro | – | Apr 17–May 15 (sow outdoors) | Aug 9–23 (sowing) |
| Parsley | Feb 20–Mar 6 | Apr 17–May 1 (transplant) Apr 10–May 1 (sow outdoors) | – |
| Dill | – | May 1–15 (sow outdoors) | Aug 9–23 (sowing) |
| Sunflower | – | May 1–15 (sow outdoors) | – |
| Asparagus (crowns) | – | Apr 3–17 (transplant) | – |
| Rhubarb (crowns) | – | Apr 3–17 (transplant) | – |
| Strawberry (plants) | – | Apr 3–17 (transplant) | Jul 26–Aug 23 (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: Rock Rapids, IA (NOAA GHCN-Daily ID USC00137147), elevation 1,350 ft, 10.6 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Sheldon, IA | 13 mi | May 5 | Sep 28 |
| Sibley, IA | 14 mi | May 5 | Oct 3 |
| Sanborn, IA | 20 mi | May 1 | Oct 7 |
The average last-frost dates of these stations span 4 days, a rough guide to local variation. See data sources & methods.
Frost questions for 51237
When is the last frost in 51237?
The average (50% chance) last spring freeze of 32°F for ZIP 51237 is May 1. For a more cautious planting date, use May 13, when only 1 year in 10 still sees a later freeze.
When is the first frost in 51237?
The average first fall freeze is October 4. In 1 year in 10 it comes by September 21.
What hardiness zone is 51237?
ZIP 51237 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 51237 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
51244 Matlock 51243 Little Rock 51234 Boyden 51232 Ashton 51246 Rock Rapids 51235 Doon 51239 Hull 51201 Sheldon
Other ZIP codes in Lyon County
51230 51235 51240 51241 51242 51243 51246 All Lyon County frost dates · Iowa frost dates
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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.