Fall in zone 5aPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 52218 (Coggon, 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, Coggon, IA (1 miles away).
- Average last spring frostMay 350% chance of a 32°F freeze after this date
- Average first fall frostOct 750% 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
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 52218 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 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 3 |
| 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 22 |
| 50% (the "average" first frost) | Oct 7 |
| 90% (late: most years have frozen by now) | Oct 20 |
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 3 | Oct 7 |
| 28°F (hard freeze) | Apr 22 | Oct 18 |
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 52218
Dates count from your average last spring frost (May 3) and first fall frost (Oct 7). 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 8–22 | May 10–24 (transplant) | – |
| Pepper (sweet and hot) | Feb 22–Mar 8 | May 17–31 (transplant) | – |
| Eggplant | Feb 22–Mar 8 | May 17–31 (transplant) | – |
| Tomatillo | Mar 8–22 | May 10–24 (transplant) | – |
| Lettuce | Mar 8–22 | Apr 12–May 3 (transplant) Apr 5–May 17 (sow outdoors) | Aug 12–Sep 2 (transplant) Jul 29–Aug 26 (sowing) |
| Spinach | – | Mar 22–Apr 12 (sow outdoors) | Aug 12–Sep 2 (sowing) |
| Kale | Mar 8–22 | Apr 5–19 (transplant) Apr 5–19 (sow outdoors) | Jul 15–Aug 12 (transplant) Jul 1–29 (sowing) |
| Collards | Mar 8–22 | Apr 5–May 3 (transplant) Apr 5–May 3 (sow outdoors) | Jul 15–Aug 12 (transplant) Jul 1–29 (sowing) |
| Broccoli | Feb 22–Mar 8 | Apr 5–19 (transplant) | Jul 1–29 (transplant) |
| Cabbage | Feb 22–Mar 8 | Apr 5–19 (transplant) | Jul 1–29 (transplant) |
| Cauliflower | Feb 22–Mar 8 | Apr 19–May 3 (transplant) | Jul 1–29 (transplant) |
| Brussels sprouts | Feb 8–22 | Apr 5–19 (transplant) | Jun 17–Jul 8 (transplant) |
| Kohlrabi | Mar 8–22 | Apr 5–19 (transplant) Apr 5–19 (sow outdoors) | Jul 29–Aug 12 (sowing) |
| Bok choy / Asian greens | – | Apr 5–19 (sow outdoors) | Aug 12–26 (sowing) |
| Arugula | – | Apr 5–May 3 (sow outdoors) | Aug 12–Sep 9 (sowing) |
| Mustard greens | – | Apr 5–26 (sow outdoors) | Aug 12–26 (sowing) |
| Swiss chard | Mar 22–Apr 5 | Apr 19–May 10 (transplant) Apr 19–May 17 (sow outdoors) | Jul 29–Aug 12 (sowing) |
| Beet | – | Apr 5–May 3 (sow outdoors) | Jul 29–Aug 12 (sowing) |
| Carrot | – | Apr 12–May 10 (sow outdoors) | Jul 15–29 (sowing) |
| Radish | – | Mar 29–May 10 (sow outdoors) | Aug 26–Sep 9 (sowing) |
| Turnip | – | Apr 5–26 (sow outdoors) | Jul 29–Aug 12 (sowing) |
| Parsnip | – | Apr 12–May 3 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 8–Apr 5 (sow outdoors) | Jul 15–29 (sowing) |
| Onion (bulbing) | Feb 8–22 | Mar 22–Apr 5 (transplant) | – |
| Green onion / scallion | – | Mar 22–Apr 19 (sow outdoors) | Jul 29–Aug 12 (sowing) |
| Leek | Feb 8–22 | Apr 5–19 (transplant) | – |
| Garlic | – | – | Aug 26–Sep 23 (sowing) |
| Shallot | – | Mar 22–Apr 5 (transplant) | Aug 26–Sep 23 (sowing) |
| Potato | – | Apr 5–19 (transplant) | Jun 17–Jul 1 (transplant) |
| Sweet potato | – | May 24–Jun 7 (transplant) | – |
| Sweet corn | – | May 10–24 (sow outdoors) | – |
| Bean, bush (snap) | – | May 10–24 (sow outdoors) | – |
| Bean, pole | – | May 10–24 (sow outdoors) | – |
| Lima bean | – | May 17–31 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 24–Jun 14 (sow outdoors) | – |
| Cucumber | Apr 5–12 | May 10–24 (transplant) May 10–24 (sow outdoors) | – |
| Summer squash / zucchini | Apr 5–12 | May 10–24 (transplant) May 10–24 (sow outdoors) | – |
| Winter squash | Apr 5–12 | May 10–24 (transplant) May 10–24 (sow outdoors) | – |
| Pumpkin | – | May 10–24 (sow outdoors) | – |
| Watermelon | Apr 5–12 | May 17–31 (transplant) May 17–31 (sow outdoors) | – |
| Cantaloupe / muskmelon | Apr 5–12 | May 17–31 (transplant) May 17–31 (sow outdoors) | – |
| Okra | Mar 22–Apr 5 | May 17–31 (transplant) May 17–31 (sow outdoors) | – |
| Celery | Feb 8–22 | May 10–17 (transplant) | – |
| Basil | Mar 22–Apr 5 | May 10–24 (transplant) May 10–24 (sow outdoors) | – |
| Cilantro | – | Apr 19–May 17 (sow outdoors) | Aug 12–26 (sowing) |
| Parsley | Feb 22–Mar 8 | Apr 19–May 3 (transplant) Apr 12–May 3 (sow outdoors) | – |
| Dill | – | May 3–17 (sow outdoors) | Aug 12–26 (sowing) |
| Sunflower | – | May 3–17 (sow outdoors) | – |
| Asparagus (crowns) | – | Apr 5–19 (transplant) | – |
| Rhubarb (crowns) | – | Apr 5–19 (transplant) | – |
| Strawberry (plants) | – | Apr 5–19 (transplant) | Jul 29–Aug 26 (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: Coggon, IA (NOAA GHCN-Daily ID USC00131705), elevation 903 ft, 1.3 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Manchester #2, IA | 13 mi | May 3 | Oct 4 |
| Cedar Rapids #1, IA | 17 mi | Apr 28 | Oct 12 |
| Anamosa 1 WNW, IA | 18 mi | May 1 | Oct 4 |
The average last-frost dates of these stations span 6 days, a rough guide to local variation. See data sources & methods.
Frost questions for 52218
When is the last frost in 52218?
The average (50% chance) last spring freeze of 32°F for ZIP 52218 is May 3. 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 52218?
The average first fall freeze is October 7. In 1 year in 10 it comes by September 22.
What hardiness zone is 52218?
ZIP 52218 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 52218 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
52330 Ryan 52219 Prairieburg 52344 52214 Central City 50654 Masonville 52202 Alburnett 52352 Walker 52213 Center Point
Other ZIP codes in Linn County
52202 52213 52214 52219 52227 52228 52233 52302 52314 52324 52328 52336 52341 52344 52352 52401 52402 52403 52404 52405 52411 All Linn County frost dates · Iowa frost dates
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- Freeze alerts
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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.