Fall in zone 5aPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 50278 (Zearing, 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, Colo, IA (10 miles away).
- Average last spring frostApr 2450% chance of a 32°F freeze after this date
- Average first fall frostOct 1250% chance of a 32°F freeze by this date
- Growing season (frost-free)170 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
54°F 50–55°F
24-hour average · latest 55°F, as of Oct 18, 2:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Ames (24 mi), Des Moines 17 E (41 mi).
4-inch depth
56°F 55°F or warmer
24-hour average · latest 56°F, as of Oct 18, 2:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Ames (24 mi), Des Moines 17 E (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 50278 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 56°F at 4 inches (estimated soil temperature, not a station reading). Fall pre-emergent (annual bluegrass, winter weeds): window open as soil cools through the 70s and 60s.
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 9 |
| 50% (the "average" last frost) | Apr 24 |
| 10% (cautious: only 1 year in 10 freezes later) | May 7 |
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 28 |
| 50% (the "average" first frost) | Oct 12 |
| 90% (late: most years have frozen by now) | Oct 26 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | May 4 | Oct 1 |
| 32°F (freeze) | Apr 24 | Oct 12 |
| 28°F (hard freeze) | Apr 14 | Oct 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 50278
Dates count from your average last spring frost (Apr 24) and first fall frost (Oct 12). 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 | Feb 27–Mar 13 | May 1–15 (transplant) | – |
| Pepper (sweet and hot) | Feb 13–27 | May 8–22 (transplant) | – |
| Eggplant | Feb 13–27 | May 8–22 (transplant) | – |
| Tomatillo | Feb 27–Mar 13 | May 1–15 (transplant) | – |
| Lettuce | Feb 27–Mar 13 | Apr 3–24 (transplant) Mar 27–May 8 (sow outdoors) | Aug 17–Sep 7 (transplant) Aug 3–31 (sowing) |
| Spinach | – | Mar 13–Apr 3 (sow outdoors) | Aug 17–Sep 7 (sowing) |
| Kale | Feb 27–Mar 13 | Mar 27–Apr 10 (transplant) Mar 27–Apr 10 (sow outdoors) | Jul 20–Aug 17 (transplant) Jul 6–Aug 3 (sowing) |
| Collards | Feb 27–Mar 13 | Mar 27–Apr 24 (transplant) Mar 27–Apr 24 (sow outdoors) | Jul 20–Aug 17 (transplant) Jul 6–Aug 3 (sowing) |
| Broccoli | Feb 13–27 | Mar 27–Apr 10 (transplant) | Jul 6–Aug 3 (transplant) |
| Cabbage | Feb 13–27 | Mar 27–Apr 10 (transplant) | Jul 6–Aug 3 (transplant) |
| Cauliflower | Feb 13–27 | Apr 10–24 (transplant) | Jul 6–Aug 3 (transplant) |
| Brussels sprouts | Jan 30–Feb 13 | Mar 27–Apr 10 (transplant) | Jun 22–Jul 13 (transplant) |
| Kohlrabi | Feb 27–Mar 13 | Mar 27–Apr 10 (transplant) Mar 27–Apr 10 (sow outdoors) | Aug 3–17 (sowing) |
| Bok choy / Asian greens | – | Mar 27–Apr 10 (sow outdoors) | Aug 17–31 (sowing) |
| Arugula | – | Mar 27–Apr 24 (sow outdoors) | Aug 17–Sep 14 (sowing) |
| Mustard greens | – | Mar 27–Apr 17 (sow outdoors) | Aug 17–31 (sowing) |
| Swiss chard | Mar 13–27 | Apr 10–May 1 (transplant) Apr 10–May 8 (sow outdoors) | Aug 3–17 (sowing) |
| Beet | – | Mar 27–Apr 24 (sow outdoors) | Aug 3–17 (sowing) |
| Carrot | – | Apr 3–May 1 (sow outdoors) | Jul 20–Aug 3 (sowing) |
| Radish | – | Mar 20–May 1 (sow outdoors) | Aug 31–Sep 14 (sowing) |
| Turnip | – | Mar 27–Apr 17 (sow outdoors) | Aug 3–17 (sowing) |
| Parsnip | – | Apr 3–24 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Feb 27–Mar 27 (sow outdoors) | Jul 20–Aug 3 (sowing) |
| Onion (bulbing) | Jan 30–Feb 13 | Mar 13–27 (transplant) | – |
| Green onion / scallion | – | Mar 13–Apr 10 (sow outdoors) | Aug 3–17 (sowing) |
| Leek | Jan 30–Feb 13 | Mar 27–Apr 10 (transplant) | – |
| Garlic | – | – | Aug 31–Sep 28 (sowing) |
| Shallot | – | Mar 13–27 (transplant) | Aug 31–Sep 28 (sowing) |
| Potato | – | Mar 27–Apr 10 (transplant) | Jun 22–Jul 6 (transplant) |
| Sweet potato | – | May 15–29 (transplant) | – |
| Sweet corn | – | May 1–15 (sow outdoors) | – |
| Bean, bush (snap) | – | May 1–15 (sow outdoors) | – |
| Bean, pole | – | May 1–15 (sow outdoors) | – |
| Lima bean | – | May 8–22 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 15–Jun 5 (sow outdoors) | – |
| Cucumber | Mar 27–Apr 3 | May 1–15 (transplant) May 1–15 (sow outdoors) | – |
| Summer squash / zucchini | Mar 27–Apr 3 | May 1–15 (transplant) May 1–15 (sow outdoors) | – |
| Winter squash | Mar 27–Apr 3 | May 1–15 (transplant) May 1–15 (sow outdoors) | – |
| Pumpkin | – | May 1–15 (sow outdoors) | – |
| Watermelon | Mar 27–Apr 3 | May 8–22 (transplant) May 8–22 (sow outdoors) | – |
| Cantaloupe / muskmelon | Mar 27–Apr 3 | May 8–22 (transplant) May 8–22 (sow outdoors) | – |
| Okra | Mar 13–27 | May 8–22 (transplant) May 8–22 (sow outdoors) | – |
| Celery | Jan 30–Feb 13 | May 1–8 (transplant) | – |
| Basil | Mar 13–27 | May 1–15 (transplant) May 1–15 (sow outdoors) | – |
| Cilantro | – | Apr 10–May 8 (sow outdoors) | Aug 17–31 (sowing) |
| Parsley | Feb 13–27 | Apr 10–24 (transplant) Apr 3–24 (sow outdoors) | – |
| Dill | – | Apr 24–May 8 (sow outdoors) | Aug 17–31 (sowing) |
| Sunflower | – | Apr 24–May 8 (sow outdoors) | – |
| Asparagus (crowns) | – | Mar 27–Apr 10 (transplant) | – |
| Rhubarb (crowns) | – | Mar 27–Apr 10 (transplant) | – |
| Strawberry (plants) | – | Mar 27–Apr 10 (transplant) | Aug 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: Colo, IA (NOAA GHCN-Daily ID USC00131710), elevation 1,000 ft, 9.6 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Eldora, IA | 18 mi | Apr 27 | Oct 10 |
| Ames 5 SE, IA | 20 mi | Apr 26 | Oct 12 |
| Marshalltown Muni AP, IA | 20 mi | Apr 30 | Oct 6 |
The average last-frost dates of these stations span 6 days, a rough guide to local variation. See data sources & methods.
Frost questions for 50278
When is the last frost in 50278?
The average (50% chance) last spring freeze of 32°F for ZIP 50278 is April 24. For a more cautious planting date, use May 7, when only 1 year in 10 still sees a later freeze.
When is the first frost in 50278?
The average first fall freeze is October 12. In 1 year in 10 it comes by September 28.
What hardiness zone is 50278?
ZIP 50278 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 50278 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
50154 McCallsburg 50239 St. Anthony 50206 New Providence 50102 Garden City 50051 Clemons 50056 Colo 50236 Roland 50122 Hubbard
Other ZIP codes in Story County
50010 50012 50013 50014 50046 50055 50056 50105 50124 50134 50154 50201 50236 50248 All Story County frost dates · Iowa frost dates
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Weekly yard timing, plus frost and soil-temperature alerts for your ZIP code.
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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.