Fall in zone 5bPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 68855 (Mason City, NE)
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, Mason City, NE (4 miles away).
- Average last spring frostMay 350% chance of a 32°F freeze after this date
- Average first fall frostOct 550% chance of a 32°F freeze by this date
- Growing season (frost-free)153 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 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 68855 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 21 |
| 50% (the "average" last frost) | May 3 |
| 10% (cautious: only 1 year in 10 freezes later) | May 18 |
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 23 |
| 50% (the "average" first frost) | Oct 5 |
| 90% (late: most years have frozen by now) | Oct 16 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | May 14 | Sep 27 |
| 32°F (freeze) | May 3 | Oct 5 |
| 28°F (hard freeze) | Apr 24 | Oct 15 |
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 68855
Dates count from your average last spring frost (May 3) and first fall frost (Oct 5). 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 10–31 (transplant) Jul 27–Aug 24 (sowing) |
| Spinach | – | Mar 22–Apr 12 (sow outdoors) | Aug 10–31 (sowing) |
| Kale | Mar 8–22 | Apr 5–19 (transplant) Apr 5–19 (sow outdoors) | Jul 13–Aug 10 (transplant) Jun 29–Jul 27 (sowing) |
| Collards | Mar 8–22 | Apr 5–May 3 (transplant) Apr 5–May 3 (sow outdoors) | Jul 13–Aug 10 (transplant) Jun 29–Jul 27 (sowing) |
| Broccoli | Feb 22–Mar 8 | Apr 5–19 (transplant) | Jun 29–Jul 27 (transplant) |
| Cabbage | Feb 22–Mar 8 | Apr 5–19 (transplant) | Jun 29–Jul 27 (transplant) |
| Cauliflower | Feb 22–Mar 8 | Apr 19–May 3 (transplant) | Jun 29–Jul 27 (transplant) |
| Brussels sprouts | Feb 8–22 | Apr 5–19 (transplant) | Jun 15–Jul 6 (transplant) |
| Kohlrabi | Mar 8–22 | Apr 5–19 (transplant) Apr 5–19 (sow outdoors) | Jul 27–Aug 10 (sowing) |
| Bok choy / Asian greens | – | Apr 5–19 (sow outdoors) | Aug 10–24 (sowing) |
| Arugula | – | Apr 5–May 3 (sow outdoors) | Aug 10–Sep 7 (sowing) |
| Mustard greens | – | Apr 5–26 (sow outdoors) | Aug 10–24 (sowing) |
| Swiss chard | Mar 22–Apr 5 | Apr 19–May 10 (transplant) Apr 19–May 17 (sow outdoors) | Jul 27–Aug 10 (sowing) |
| Beet | – | Apr 5–May 3 (sow outdoors) | Jul 27–Aug 10 (sowing) |
| Carrot | – | Apr 12–May 10 (sow outdoors) | Jul 13–27 (sowing) |
| Radish | – | Mar 29–May 10 (sow outdoors) | Aug 24–Sep 7 (sowing) |
| Turnip | – | Apr 5–26 (sow outdoors) | Jul 27–Aug 10 (sowing) |
| Parsnip | – | Apr 12–May 3 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 8–Apr 5 (sow outdoors) | Jul 13–27 (sowing) |
| Onion (bulbing) | Feb 8–22 | Mar 22–Apr 5 (transplant) | – |
| Green onion / scallion | – | Mar 22–Apr 19 (sow outdoors) | Jul 27–Aug 10 (sowing) |
| Leek | Feb 8–22 | Apr 5–19 (transplant) | – |
| Garlic | – | – | Aug 24–Sep 21 (sowing) |
| Shallot | – | Mar 22–Apr 5 (transplant) | Aug 24–Sep 21 (sowing) |
| Potato | – | Apr 5–19 (transplant) | Jun 15–29 (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 10–24 (sowing) |
| Parsley | Feb 22–Mar 8 | Apr 19–May 3 (transplant) Apr 12–May 3 (sow outdoors) | – |
| Dill | – | May 3–17 (sow outdoors) | Aug 10–24 (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 27–Aug 24 (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.
Plants that do well here
Nebraska has a university or garden plant program: GreatPlants. Plant frost-tender annuals after May 3 here (the average last frost). Not affiliated with the program.
Where these numbers come from
Station: Mason City, NE (NOAA GHCN-Daily ID USC00255250), elevation 2,292 ft, 3.9 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Loup City, NE | 20 mi | May 2 | Oct 8 |
| Oconto, NE | 23 mi | May 10 | Oct 1 |
| Ravenna, NE | 23 mi | May 4 | Oct 3 |
The average last-frost dates of these stations span 8 days, a rough guide to local variation. See data sources & methods.
Frost questions for 68855
When is the last frost in 68855?
The average (50% chance) last spring freeze of 32°F for ZIP 68855 is May 3. For a more cautious planting date, use May 18, when only 1 year in 10 still sees a later freeze.
When is the first frost in 68855?
The average first fall freeze is October 5. In 1 year in 10 it comes by September 23.
What hardiness zone is 68855?
ZIP 68855 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 68855 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
68852 Litchfield 68814 Ansley 68858 Miller 68844 Hazard 68878 Sumner 68866 Pleasanton 68812 Amherst 68881 Westerville
Other ZIP codes in Custer County
68813 68814 68822 68825 68828 68856 68860 68874 68881 69120 All Custer County frost dates · Nebraska 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.