Fall in zone 5aPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 80447 (Grand Lake, 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, Grand Lake 6 SSW, CO (8 miles away).
- Average last spring frostJun 1350% chance of a 32°F freeze after this date
- Average first fall frostSep 750% chance of a 32°F freeze by this date
- Growing season (frost-free)84 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
42°F Below 50°F
24-hour average · latest 41°F, as of Oct 18, 1:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Boulder 14 W (23 mi).
4-inch depth
42°F Below 50°F
24-hour average · latest 42°F, as of Oct 18, 1:00 AM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Boulder 14 W (23 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 80447 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 42°F at 4 inches (estimated soil temperature, not a station reading). Fall pre-emergent window is mostly past. Next: spring, when soil reaches 50°F (typically 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) | Jun 1 |
| 50% (the "average" last frost) | Jun 13 |
| 10% (cautious: only 1 year in 10 freezes later) | Jun 28 |
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 21 |
| 50% (the "average" first frost) | Sep 7 |
| 90% (late: most years have frozen by now) | Sep 21 |
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 13 | Sep 7 |
| 28°F (hard freeze) | May 26 | Sep 22 |
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 80447
Dates count from your average last spring frost (Jun 13) and first fall frost (Sep 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 | Apr 18–May 2 | Jun 20–Jul 4 (transplant) | – |
| Pepper (sweet and hot) | Apr 4–18 | Jun 27–Jul 11 (transplant) | – |
| Eggplant | Apr 4–18 | Jun 27–Jul 11 (transplant) | – |
| Tomatillo | Apr 18–May 2 | Jun 20–Jul 4 (transplant) | – |
| Lettuce | Apr 18–May 2 | May 23–Jun 13 (transplant) May 16–Jun 27 (sow outdoors) | Jul 13–Aug 3 (transplant) Jun 29–Jul 27 (sowing) |
| Spinach | – | May 2–23 (sow outdoors) | Jul 13–Aug 3 (sowing) |
| Kale | Apr 18–May 2 | May 16–30 (transplant) May 16–30 (sow outdoors) | Jun 15–Jul 13 (transplant) Jun 1–29 (sowing) |
| Collards | Apr 18–May 2 | May 16–Jun 13 (transplant) May 16–Jun 13 (sow outdoors) | Jun 15–Jul 13 (transplant) |
| Broccoli | Apr 4–18 | May 16–30 (transplant) | Jun 1–29 (transplant) |
| Cabbage | Apr 4–18 | May 16–30 (transplant) | Jun 1–29 (transplant) |
| Cauliflower | Apr 4–18 | May 30–Jun 13 (transplant) | – |
| Brussels sprouts | Mar 21–Apr 4 | May 16–30 (transplant) | – |
| Kohlrabi | Apr 18–May 2 | May 16–30 (transplant) May 16–30 (sow outdoors) | Jun 29–Jul 13 (sowing) |
| Bok choy / Asian greens | – | May 16–30 (sow outdoors) | Jul 13–27 (sowing) |
| Arugula | – | May 16–Jun 13 (sow outdoors) | Jul 13–Aug 10 (sowing) |
| Mustard greens | – | May 16–Jun 6 (sow outdoors) | Jul 13–27 (sowing) |
| Swiss chard | May 2–16 | May 30–Jun 20 (transplant) May 30–Jun 27 (sow outdoors) | Jun 29–Jul 13 (sowing) |
| Beet | – | May 16–Jun 13 (sow outdoors) | Jun 29–Jul 13 (sowing) |
| Carrot | – | May 23–Jun 20 (sow outdoors) | – |
| Radish | – | May 9–Jun 20 (sow outdoors) | Jul 27–Aug 10 (sowing) |
| Turnip | – | May 16–Jun 6 (sow outdoors) | Jun 29–Jul 13 (sowing) |
| Parsnip | – | May 23–Jun 13 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Apr 18–May 16 (sow outdoors) | Jun 15–29 (sowing) |
| Onion (bulbing) | Mar 21–Apr 4 | May 2–16 (transplant) | – |
| Green onion / scallion | – | May 2–30 (sow outdoors) | Jun 29–Jul 13 (sowing) |
| Leek | Mar 21–Apr 4 | May 16–30 (transplant) | – |
| Garlic | – | – | Jul 27–Aug 24 (sowing) |
| Shallot | – | May 2–16 (transplant) | Jul 27–Aug 24 (sowing) |
| Potato | – | May 16–30 (transplant) | – |
| Sweet potato | – | Jul 4–18 (transplant) | – |
| Sweet corn | – | Jun 20–Jul 4 (sow outdoors) | – |
| Bean, bush (snap) | – | Jun 20–Jul 4 (sow outdoors) | – |
| Bean, pole | – | Jun 20–Jul 4 (sow outdoors) | – |
| Lima bean | – | Jun 27–Jul 11 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Jul 4–25 (sow outdoors) | – |
| Cucumber | May 16–23 | Jun 20–Jul 4 (transplant) Jun 20–Jul 4 (sow outdoors) | – |
| Summer squash / zucchini | May 16–23 | Jun 20–Jul 4 (transplant) Jun 20–Jul 4 (sow outdoors) | – |
| Winter squash | May 16–23 | Jun 20–Jul 4 (transplant) Jun 20–Jul 4 (sow outdoors) | – |
| Pumpkin | – | Jun 20–Jul 4 (sow outdoors) | – |
| Watermelon | May 16–23 | Jun 27–Jul 11 (transplant) Jun 27–Jul 11 (sow outdoors) | – |
| Cantaloupe / muskmelon | May 16–23 | Jun 27–Jul 11 (transplant) Jun 27–Jul 11 (sow outdoors) | – |
| Okra | May 2–16 | Jun 27–Jul 11 (transplant) Jun 27–Jul 11 (sow outdoors) | – |
| Celery | Mar 21–Apr 4 | Jun 20–27 (transplant) | – |
| Basil | May 2–16 | Jun 20–Jul 4 (transplant) Jun 20–Jul 4 (sow outdoors) | – |
| Cilantro | – | May 30–Jun 27 (sow outdoors) | Jul 13–27 (sowing) |
| Parsley | Apr 4–18 | May 30–Jun 13 (transplant) May 23–Jun 13 (sow outdoors) | – |
| Dill | – | Jun 13–27 (sow outdoors) | Jul 13–27 (sowing) |
| Sunflower | – | Jun 13–27 (sow outdoors) | – |
| Asparagus (crowns) | – | May 16–30 (transplant) | – |
| Rhubarb (crowns) | – | May 16–30 (transplant) | – |
| Strawberry (plants) | – | May 16–30 (transplant) | Jun 29–Jul 27 (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 13 here (the average last frost). Not affiliated with the program.
Where these numbers come from
Station: Grand Lake 6 SSW, CO (NOAA GHCN-Daily ID USC00053500), elevation 8,288 ft, 8.0 miles from the ZIP's center point. NOAA completeness flag: S (standard, 24+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Estes Park 3 SSE, CO | 16 mi | May 30 | Sep 17 |
| Allenspark 3NW, CO | 17 mi | Jun 14 | Sep 12 |
| Boulder 14 W, CO | 23 mi | Jun 21 | Sep 2 |
The average last-frost dates of these stations span 22 days, a rough guide to local variation. See data sources & methods.
Frost questions for 80447
When is the last frost in 80447?
The average (50% chance) last spring freeze of 32°F for ZIP 80447 is June 13. For a more cautious planting date, use June 28, when only 1 year in 10 still sees a later freeze.
When is the first frost in 80447?
The average first fall freeze is September 7. In 1 year in 10 it comes by August 21.
What hardiness zone is 80447?
ZIP 80447 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 80447 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
80446 Granby 80510 Allenspark 80517 Estes Park 80481 Bark Ranch 80478 Tabernash 80473 80451 Hot Sulphur Springs 80540 Lyons
Other ZIP codes in Grand County
80442 80446 80451 80459 80468 80478 80482 All Grand County frost dates · Colorado 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.