Frost dates for ZIP 52221 (Guernsey, 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, Belle Plaine, IA (17 miles away).
- Average last spring frostApr 2850% chance of a 32°F freeze after this date
- Average first fall frostOct 1050% chance of a 32°F freeze by this date
- Growing season (frost-free)165 daysmedian, 32°F threshold
- USDA hardiness zone5b-15 to -10°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
57°F 55°F or warmer
24-hour average · latest 57°F, as of Oct 17, 9:00 PM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Des Moines 17 E (50 mi).
4-inch depth
59°F 55°F or warmer
24-hour average · latest 58°F, as of Oct 17, 9:00 PM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Des Moines 17 E (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 52221 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 59°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 14 |
| 50% (the "average" last frost) | Apr 28 |
| 10% (cautious: only 1 year in 10 freezes later) | May 11 |
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 26 |
| 50% (the "average" first frost) | Oct 10 |
| 90% (late: most years have frozen by now) | Oct 23 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | May 6 | Oct 1 |
| 32°F (freeze) | Apr 28 | Oct 10 |
| 28°F (hard freeze) | Apr 16 | Oct 21 |
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 52221
Dates count from your average last spring frost (Apr 28) and first fall frost (Oct 10). 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 3–17 | May 5–19 (transplant) | – |
| Pepper (sweet and hot) | Feb 17–Mar 3 | May 12–26 (transplant) | – |
| Eggplant | Feb 17–Mar 3 | May 12–26 (transplant) | – |
| Tomatillo | Mar 3–17 | May 5–19 (transplant) | – |
| Lettuce | Mar 3–17 | Apr 7–28 (transplant) Mar 31–May 12 (sow outdoors) | Aug 15–Sep 5 (transplant) Aug 1–29 (sowing) |
| Spinach | – | Mar 17–Apr 7 (sow outdoors) | Aug 15–Sep 5 (sowing) |
| Kale | Mar 3–17 | Mar 31–Apr 14 (transplant) Mar 31–Apr 14 (sow outdoors) | Jul 18–Aug 15 (transplant) Jul 4–Aug 1 (sowing) |
| Collards | Mar 3–17 | Mar 31–Apr 28 (transplant) Mar 31–Apr 28 (sow outdoors) | Jul 18–Aug 15 (transplant) Jul 4–Aug 1 (sowing) |
| Broccoli | Feb 17–Mar 3 | Mar 31–Apr 14 (transplant) | Jul 4–Aug 1 (transplant) |
| Cabbage | Feb 17–Mar 3 | Mar 31–Apr 14 (transplant) | Jul 4–Aug 1 (transplant) |
| Cauliflower | Feb 17–Mar 3 | Apr 14–28 (transplant) | Jul 4–Aug 1 (transplant) |
| Brussels sprouts | Feb 3–17 | Mar 31–Apr 14 (transplant) | Jun 20–Jul 11 (transplant) |
| Kohlrabi | Mar 3–17 | Mar 31–Apr 14 (transplant) Mar 31–Apr 14 (sow outdoors) | Aug 1–15 (sowing) |
| Bok choy / Asian greens | – | Mar 31–Apr 14 (sow outdoors) | Aug 15–29 (sowing) |
| Arugula | – | Mar 31–Apr 28 (sow outdoors) | Aug 15–Sep 12 (sowing) |
| Mustard greens | – | Mar 31–Apr 21 (sow outdoors) | Aug 15–29 (sowing) |
| Swiss chard | Mar 17–31 | Apr 14–May 5 (transplant) Apr 14–May 12 (sow outdoors) | Aug 1–15 (sowing) |
| Beet | – | Mar 31–Apr 28 (sow outdoors) | Aug 1–15 (sowing) |
| Carrot | – | Apr 7–May 5 (sow outdoors) | Jul 18–Aug 1 (sowing) |
| Radish | – | Mar 24–May 5 (sow outdoors) | Aug 29–Sep 12 (sowing) |
| Turnip | – | Mar 31–Apr 21 (sow outdoors) | Aug 1–15 (sowing) |
| Parsnip | – | Apr 7–28 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 3–31 (sow outdoors) | Jul 18–Aug 1 (sowing) |
| Onion (bulbing) | Feb 3–17 | Mar 17–31 (transplant) | – |
| Green onion / scallion | – | Mar 17–Apr 14 (sow outdoors) | Aug 1–15 (sowing) |
| Leek | Feb 3–17 | Mar 31–Apr 14 (transplant) | – |
| Garlic | – | – | Aug 29–Sep 26 (sowing) |
| Shallot | – | Mar 17–31 (transplant) | Aug 29–Sep 26 (sowing) |
| Potato | – | Mar 31–Apr 14 (transplant) | Jun 20–Jul 4 (transplant) |
| Sweet potato | – | May 19–Jun 2 (transplant) | – |
| Sweet corn | – | May 5–19 (sow outdoors) | – |
| Bean, bush (snap) | – | May 5–19 (sow outdoors) | – |
| Bean, pole | – | May 5–19 (sow outdoors) | – |
| Lima bean | – | May 12–26 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 19–Jun 9 (sow outdoors) | – |
| Cucumber | Mar 31–Apr 7 | May 5–19 (transplant) May 5–19 (sow outdoors) | – |
| Summer squash / zucchini | Mar 31–Apr 7 | May 5–19 (transplant) May 5–19 (sow outdoors) | – |
| Winter squash | Mar 31–Apr 7 | May 5–19 (transplant) May 5–19 (sow outdoors) | – |
| Pumpkin | – | May 5–19 (sow outdoors) | – |
| Watermelon | Mar 31–Apr 7 | May 12–26 (transplant) May 12–26 (sow outdoors) | – |
| Cantaloupe / muskmelon | Mar 31–Apr 7 | May 12–26 (transplant) May 12–26 (sow outdoors) | – |
| Okra | Mar 17–31 | May 12–26 (transplant) May 12–26 (sow outdoors) | – |
| Celery | Feb 3–17 | May 5–12 (transplant) | – |
| Basil | Mar 17–31 | May 5–19 (transplant) May 5–19 (sow outdoors) | – |
| Cilantro | – | Apr 14–May 12 (sow outdoors) | Aug 15–29 (sowing) |
| Parsley | Feb 17–Mar 3 | Apr 14–28 (transplant) Apr 7–28 (sow outdoors) | – |
| Dill | – | Apr 28–May 12 (sow outdoors) | Aug 15–29 (sowing) |
| Sunflower | – | Apr 28–May 12 (sow outdoors) | – |
| Asparagus (crowns) | – | Mar 31–Apr 14 (transplant) | – |
| Rhubarb (crowns) | – | Mar 31–Apr 14 (transplant) | – |
| Strawberry (plants) | – | Mar 31–Apr 14 (transplant) | Aug 1–29 (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: Belle Plaine, IA (NOAA GHCN-Daily ID USC00130600), elevation 810 ft, 16.8 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Williamsburg 1E, IA | 17 mi | Apr 28 | Oct 9 |
| Sigourney, IA | 22 mi | Apr 24 | Oct 15 |
| Grinnell 3 SW, IA | 22 mi | May 3 | Oct 6 |
The average last-frost dates of these stations span 10 days, a rough guide to local variation. See data sources & methods.
Frost questions for 52221
When is the last frost in 52221?
The average (50% chance) last spring freeze of 32°F for ZIP 52221 is April 28. For a more cautious planting date, use May 11, when only 1 year in 10 still sees a later freeze.
When is the first frost in 52221?
The average first fall freeze is October 10. In 1 year in 10 it comes by September 26.
What hardiness zone is 52221?
ZIP 52221 is in USDA zone 5b (-15 to -10°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 52221 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
52222 Deep River 52347 Victor 52251 Ladora 52211 Holiday Lake 52308 Millersburg 50104 Gibson 50171 Montezuma 52232 Hartwick
Other ZIP codes in Poweshiek County
50112 50157 50171 50242 52211 52222 52232 All Poweshiek County frost dates · Iowa frost dates
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