Fall in zone 5bPhoto: Dietmar Rabich, CC BY-SA 4.0, via Wikimedia Commons
Frost dates for ZIP 80455 (Glendale, 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, Boulder 14 W, CO (9 miles away).
- Average last spring frostJun 2150% chance of a 32°F freeze after this date
- Average first fall frostSep 250% chance of a 32°F freeze by this date
- Growing season (frost-free)71 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
42°F Below 50°F
24-hour average · latest 41°F, as of Oct 18, 1:00 AM CDT
Measured at NOAA USCRN station Boulder 14 W, 8 mi away. Daily averages: Thu 42°, Fri 40°, Sat 41°.
4-inch depth
42°F Below 50°F
24-hour average · latest 42°F, as of Oct 18, 1:00 AM CDT
Measured at NOAA USCRN station Boulder 14 W, 8 mi away. Daily averages: Thu 44°, Fri 42°, Sat 42°.
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 80455 load here. You can also open the NWS forecast for this ZIP.
Pre-emergent
Soil is 42°F at 4 inches. 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 7 |
| 50% (the "average" last frost) | Jun 21 |
| 10% (cautious: only 1 year in 10 freezes later) | Jul 4 |
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 17 |
| 50% (the "average" first frost) | Sep 2 |
| 90% (late: most years have frozen by now) | Sep 15 |
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 21 | Sep 2 |
| 28°F (hard freeze) | Jun 4 | Sep 14 |
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 80455
Dates count from your average last spring frost (Jun 21) and first fall frost (Sep 2). 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 26–May 10 | Jun 28–Jul 12 (transplant) | – |
| Pepper (sweet and hot) | Apr 12–26 | Jul 5–19 (transplant) | – |
| Eggplant | Apr 12–26 | Jul 5–19 (transplant) | – |
| Tomatillo | Apr 26–May 10 | Jun 28–Jul 12 (transplant) | – |
| Lettuce | Apr 26–May 10 | May 31–Jun 21 (transplant) May 24–Jul 5 (sow outdoors) | Jul 8–29 (transplant) |
| Spinach | – | May 10–31 (sow outdoors) | Jul 8–29 (sowing) |
| Kale | Apr 26–May 10 | May 24–Jun 7 (transplant) May 24–Jun 7 (sow outdoors) | Jun 10–Jul 8 (transplant) |
| Collards | Apr 26–May 10 | May 24–Jun 21 (transplant) May 24–Jun 21 (sow outdoors) | – |
| Broccoli | Apr 12–26 | May 24–Jun 7 (transplant) | – |
| Cabbage | Apr 12–26 | May 24–Jun 7 (transplant) | – |
| Cauliflower | Apr 12–26 | Jun 7–21 (transplant) | – |
| Brussels sprouts | Mar 29–Apr 12 | May 24–Jun 7 (transplant) | – |
| Kohlrabi | Apr 26–May 10 | May 24–Jun 7 (transplant) May 24–Jun 7 (sow outdoors) | Jun 24–Jul 8 (sowing) |
| Bok choy / Asian greens | – | May 24–Jun 7 (sow outdoors) | Jul 8–22 (sowing) |
| Arugula | – | May 24–Jun 21 (sow outdoors) | Jul 8–Aug 5 (sowing) |
| Mustard greens | – | May 24–Jun 14 (sow outdoors) | Jul 8–22 (sowing) |
| Swiss chard | May 10–24 | Jun 7–28 (transplant) Jun 7–Jul 5 (sow outdoors) | – |
| Beet | – | May 24–Jun 21 (sow outdoors) | Jun 24–Jul 8 (sowing) |
| Carrot | – | May 31–Jun 28 (sow outdoors) | – |
| Radish | – | May 17–Jun 28 (sow outdoors) | Jul 22–Aug 5 (sowing) |
| Turnip | – | May 24–Jun 14 (sow outdoors) | Jun 24–Jul 8 (sowing) |
| Parsnip | – | May 31–Jun 21 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Apr 26–May 24 (sow outdoors) | Jun 10–24 (sowing) |
| Onion (bulbing) | Mar 29–Apr 12 | May 10–24 (transplant) | – |
| Green onion / scallion | – | May 10–Jun 7 (sow outdoors) | Jun 24–Jul 8 (sowing) |
| Leek | Mar 29–Apr 12 | May 24–Jun 7 (transplant) | – |
| Garlic | – | – | Jul 22–Aug 19 (sowing) |
| Shallot | – | May 10–24 (transplant) | Jul 22–Aug 19 (sowing) |
| Potato | – | May 24–Jun 7 (transplant) | – |
| Sweet potato | – | Jul 12–26 (transplant) | – |
| Sweet corn | – | Jun 28–Jul 12 (sow outdoors) | – |
| Bean, bush (snap) | – | Jun 28–Jul 12 (sow outdoors) | – |
| Bean, pole | – | Jun 28–Jul 12 (sow outdoors) | – |
| Lima bean | – | Jul 5–19 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | Jul 12–Aug 2 (sow outdoors) | – |
| Cucumber | May 24–31 | Jun 28–Jul 12 (transplant) Jun 28–Jul 12 (sow outdoors) | – |
| Summer squash / zucchini | May 24–31 | Jun 28–Jul 12 (transplant) Jun 28–Jul 12 (sow outdoors) | – |
| Winter squash | May 24–31 | Jun 28–Jul 12 (transplant) Jun 28–Jul 12 (sow outdoors) | – |
| Pumpkin | – | Jun 28–Jul 12 (sow outdoors) | – |
| Watermelon | May 24–31 | Jul 5–19 (transplant) Jul 5–19 (sow outdoors) | – |
| Cantaloupe / muskmelon | May 24–31 | Jul 5–19 (transplant) Jul 5–19 (sow outdoors) | – |
| Okra | May 10–24 | Jul 5–19 (transplant) Jul 5–19 (sow outdoors) | – |
| Celery | Mar 29–Apr 12 | Jun 28–Jul 5 (transplant) | – |
| Basil | May 10–24 | Jun 28–Jul 12 (transplant) Jun 28–Jul 12 (sow outdoors) | – |
| Cilantro | – | Jun 7–Jul 5 (sow outdoors) | Jul 8–22 (sowing) |
| Parsley | Apr 12–26 | Jun 7–21 (transplant) May 31–Jun 21 (sow outdoors) | – |
| Dill | – | Jun 21–Jul 5 (sow outdoors) | Jul 8–22 (sowing) |
| Sunflower | – | Jun 21–Jul 5 (sow outdoors) | – |
| Asparagus (crowns) | – | May 24–Jun 7 (transplant) | – |
| Rhubarb (crowns) | – | May 24–Jun 7 (transplant) | – |
| Strawberry (plants) | – | May 24–Jun 7 (transplant) | Jun 24–Jul 22 (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 21 here (the average last frost). Not affiliated with the program.
Where these numbers come from
Station: Boulder 14 W, CO (NOAA GHCN-Daily ID USW00094075), elevation 9,828 ft, 8.6 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Boulder, CO | 10 mi | May 6 | Oct 5 |
| Allenspark 3NW, CO | 11 mi | Jun 14 | Sep 12 |
| Gross Rsvr, CO | 11 mi | May 24 | Sep 23 |
The average last-frost dates of these stations span 46 days, a rough guide to local variation. See data sources & methods.
Frost questions for 80455
When is the last frost in 80455?
The average (50% chance) last spring freeze of 32°F for ZIP 80455 is June 21. For a more cautious planting date, use July 4, when only 1 year in 10 still sees a later freeze.
When is the first frost in 80455?
The average first fall freeze is September 2. In 1 year in 10 it comes by August 17.
What hardiness zone is 80455?
ZIP 80455 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 80455 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
80302 Lazy Acres 80304 Boulder 80540 Lyons 80481 Bark Ranch 80310 Boulder 80466 Eldora 80301 Boulder 80471
Other ZIP codes in Boulder County
80025 80026 80027 80301 80302 80303 80304 80305 80310 80466 80471 80481 80501 80503 80510 80540 80544 All Boulder County frost dates · Colorado frost dates
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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.