Fall in zone 5aPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 80428 (Routt County, CO)
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, Steamboat Springs, CO (25 miles away).
Station is a bit far
The nearest station with freeze normals is over 40 km away, so dates here may be off by a week or more.
- Average last spring frostJun 950% chance of a 32°F freeze after this date
- Average first fall frostSep 1250% chance of a 32°F freeze by this date
- Growing season (frost-free)93 daysmedian, 32°F threshold
- USDA hardiness zone5a-20 to -15°F avg. coldest night
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Frost and freeze alerts from the NWS forecast for 80428, the spring soil-temperature heads-up for pre-emergent, and a short weekly yard-timing email.
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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 80428 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 mid-May.
Fertilizer window
Lawn region: Mountain West and High Plains. 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) | May 25 |
| 50% (the "average" last frost) | Jun 9 |
| 10% (cautious: only 1 year in 10 freezes later) | Jun 24 |
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) | Aug 31 |
| 50% (the "average" first frost) | Sep 12 |
| 90% (late: most years have frozen by now) | Sep 24 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | n/a | n/a |
| 32°F (freeze) | Jun 9 | Sep 12 |
| 28°F (hard freeze) | May 20 | Sep 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 80428
Dates count from your average last spring frost (Jun 9) and first fall frost (Sep 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 | Apr 14–28 | Jun 16–30 (transplant) | – |
| Pepper (sweet and hot) | Mar 31–Apr 14 | Jun 23–Jul 7 (transplant) | – |
| Eggplant | Mar 31–Apr 14 | Jun 23–Jul 7 (transplant) | – |
| Tomatillo | Apr 14–28 | Jun 16–30 (transplant) | – |
| Lettuce | Apr 14–28 | May 19–Jun 9 (transplant) May 12–Jun 23 (sow outdoors) | Jul 18–Aug 8 (transplant) Jul 4–Aug 1 (sowing) |
| Spinach | – | Apr 28–May 19 (sow outdoors) | Jul 18–Aug 8 (sowing) |
| Kale | Apr 14–28 | May 12–26 (transplant) May 12–26 (sow outdoors) | Jun 20–Jul 18 (transplant) Jun 6–Jul 4 (sowing) |
| Collards | Apr 14–28 | May 12–Jun 9 (transplant) May 12–Jun 9 (sow outdoors) | Jun 20–Jul 18 (transplant) |
| Broccoli | Mar 31–Apr 14 | May 12–26 (transplant) | Jun 6–Jul 4 (transplant) |
| Cabbage | Mar 31–Apr 14 | May 12–26 (transplant) | Jun 6–Jul 4 (transplant) |
| Cauliflower | Mar 31–Apr 14 | May 26–Jun 9 (transplant) | – |
| Brussels sprouts | Mar 17–31 | May 12–26 (transplant) | – |
| Kohlrabi | Apr 14–28 | May 12–26 (transplant) May 12–26 (sow outdoors) | Jul 4–18 (sowing) |
| Bok choy / Asian greens | – | May 12–26 (sow outdoors) | Jul 18–Aug 1 (sowing) |
| Arugula | – | May 12–Jun 9 (sow outdoors) | Jul 18–Aug 15 (sowing) |
| Mustard greens | – | May 12–Jun 2 (sow outdoors) | Jul 18–Aug 1 (sowing) |
| Swiss chard | Apr 28–May 12 | May 26–Jun 16 (transplant) May 26–Jun 23 (sow outdoors) | Jul 4–18 (sowing) |
| Beet | – | May 12–Jun 9 (sow outdoors) | Jul 4–18 (sowing) |
| Carrot | – | May 19–Jun 16 (sow outdoors) | Jun 20–Jul 4 (sowing) |
| Radish | – | May 5–Jun 16 (sow outdoors) | Aug 1–15 (sowing) |
| Turnip | – | May 12–Jun 2 (sow outdoors) | Jul 4–18 (sowing) |
| Parsnip | – | May 19–Jun 9 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Apr 14–May 12 (sow outdoors) | Jun 20–Jul 4 (sowing) |
| Onion (bulbing) | Mar 17–31 | Apr 28–May 12 (transplant) | – |
| Green onion / scallion | – | Apr 28–May 26 (sow outdoors) | Jul 4–18 (sowing) |
| Leek | Mar 17–31 | May 12–26 (transplant) | – |
| Garlic | – | – | Aug 1–29 (sowing) |
| Shallot | – | Apr 28–May 12 (transplant) | Aug 1–29 (sowing) |
| Potato | – | May 12–26 (transplant) | – |
| Sweet potato | – | Jun 30–Jul 14 (transplant) | – |
| Sweet corn | – | Jun 16–30 (sow outdoors) | – |
| Bean, bush (snap) | – | Jun 16–30 (sow outdoors) | – |
| Bean, pole | – | Jun 16–30 (sow outdoors) | – |
| Lima bean | – | Jun 23–Jul 7 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Jun 30–Jul 21 (sow outdoors) | – |
| Cucumber | May 12–19 | Jun 16–30 (transplant) Jun 16–30 (sow outdoors) | – |
| Summer squash / zucchini | May 12–19 | Jun 16–30 (transplant) Jun 16–30 (sow outdoors) | – |
| Winter squash | May 12–19 | Jun 16–30 (transplant) Jun 16–30 (sow outdoors) | – |
| Pumpkin | – | Jun 16–30 (sow outdoors) | – |
| Watermelon | May 12–19 | Jun 23–Jul 7 (transplant) Jun 23–Jul 7 (sow outdoors) | – |
| Cantaloupe / muskmelon | May 12–19 | Jun 23–Jul 7 (transplant) Jun 23–Jul 7 (sow outdoors) | – |
| Okra | Apr 28–May 12 | Jun 23–Jul 7 (transplant) Jun 23–Jul 7 (sow outdoors) | – |
| Celery | Mar 17–31 | Jun 16–23 (transplant) | – |
| Basil | Apr 28–May 12 | Jun 16–30 (transplant) Jun 16–30 (sow outdoors) | – |
| Cilantro | – | May 26–Jun 23 (sow outdoors) | Jul 18–Aug 1 (sowing) |
| Parsley | Mar 31–Apr 14 | May 26–Jun 9 (transplant) May 19–Jun 9 (sow outdoors) | – |
| Dill | – | Jun 9–23 (sow outdoors) | Jul 18–Aug 1 (sowing) |
| Sunflower | – | Jun 9–23 (sow outdoors) | – |
| Asparagus (crowns) | – | May 12–26 (transplant) | – |
| Rhubarb (crowns) | – | May 12–26 (transplant) | – |
| Strawberry (plants) | – | May 12–26 (transplant) | Jul 4–Aug 1 (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
Colorado has a university or garden plant program: Plant Select®. Plant frost-tender annuals after June 9 here (the average last frost). Not affiliated with the program.
Where these numbers come from
Station: Steamboat Springs, CO (NOAA GHCN-Daily ID USC00057936), elevation 6,866 ft, 25.1 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Hayden, CO | 30 mi | Jun 1 | Sep 20 |
| Craig Moffat Co AP, CO | 39 mi | Jun 6 | Sep 12 |
| Baggs, WY | 41 mi | Jun 1 | Sep 18 |
The average last-frost dates of these stations span 8 days, a rough guide to local variation. See data sources & methods.
Frost questions for 80428
When is the last frost in 80428?
The average (50% chance) last spring freeze of 32°F for ZIP 80428 is June 9. For a more cautious planting date, use June 24, when only 1 year in 10 still sees a later freeze.
When is the first frost in 80428?
The average first fall freeze is September 12. In 1 year in 10 it comes by August 31.
What hardiness zone is 80428?
ZIP 80428 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 80428 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
81653 80487 Steamboat Springs 82325 Encampment 82332 81639 Hayden 80480 Walden 82323 Dixon 80434
Other ZIP codes in Routt County
80463 80467 80469 80479 80483 80487 81639 81653 All Routt County frost dates · Colorado frost dates
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Weekly yard timing, plus frost and soil-temperature alerts for your ZIP code.
- 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.