Frost dates for ZIP 80231 (Denver, 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, Cherry Creek Dam, CO (4 miles away).
- Average last spring frostMay 750% chance of a 32°F freeze after this date
- Average first fall frostOct 850% chance of a 32°F freeze by this date
- Growing season (frost-free)152 daysmedian, 32°F threshold
- USDA hardiness zone6a-10 to -5°F avg. coldest night
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This week in your yard
As of Oct 17, 2026, from your frost dates, zone and soil temperature. Lawn timing · Vegetables · Pruning · Plants
Soil temperature now
2-inch depth
41°F Below 50°F
24-hour average · latest 44°F, as of Oct 17, 9:00 PM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Boulder 14 W (43 mi).
4-inch depth
42°F Below 50°F
24-hour average · latest 45°F, as of Oct 17, 9:00 PM CDT
Estimate Not a measurement at this ZIP: distance-weighted average of Boulder 14 W (43 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 80231 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) | Apr 26 |
| 50% (the "average" last frost) | May 7 |
| 10% (cautious: only 1 year in 10 freezes later) | May 21 |
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 25 |
| 50% (the "average" first frost) | Oct 8 |
| 90% (late: most years have frozen by now) | Oct 19 |
Light frost, freeze and hard freeze
| Threshold | Last spring (50%) | First fall (50%) |
|---|---|---|
| 36°F (light frost possible on clear, calm nights) | May 18 | Sep 30 |
| 32°F (freeze) | May 7 | Oct 8 |
| 28°F (hard freeze) | Apr 29 | 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 80231
Dates count from your average last spring frost (May 7) and first fall frost (Oct 8). 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 12–26 | May 14–28 (transplant) | – |
| Pepper (sweet and hot) | Feb 26–Mar 12 | May 21–Jun 4 (transplant) | – |
| Eggplant | Feb 26–Mar 12 | May 21–Jun 4 (transplant) | – |
| Tomatillo | Mar 12–26 | May 14–28 (transplant) | – |
| Lettuce | Mar 12–26 | Apr 16–May 7 (transplant) Apr 9–May 21 (sow outdoors) | Aug 13–Sep 3 (transplant) Jul 30–Aug 27 (sowing) |
| Spinach | – | Mar 26–Apr 16 (sow outdoors) | Aug 13–Sep 3 (sowing) |
| Kale | Mar 12–26 | Apr 9–23 (transplant) Apr 9–23 (sow outdoors) | Jul 16–Aug 13 (transplant) Jul 2–30 (sowing) |
| Collards | Mar 12–26 | Apr 9–May 7 (transplant) Apr 9–May 7 (sow outdoors) | Jul 16–Aug 13 (transplant) Jul 2–30 (sowing) |
| Broccoli | Feb 26–Mar 12 | Apr 9–23 (transplant) | Jul 2–30 (transplant) |
| Cabbage | Feb 26–Mar 12 | Apr 9–23 (transplant) | Jul 2–30 (transplant) |
| Cauliflower | Feb 26–Mar 12 | Apr 23–May 7 (transplant) | Jul 2–30 (transplant) |
| Brussels sprouts | Feb 12–26 | Apr 9–23 (transplant) | Jun 18–Jul 9 (transplant) |
| Kohlrabi | Mar 12–26 | Apr 9–23 (transplant) Apr 9–23 (sow outdoors) | Jul 30–Aug 13 (sowing) |
| Bok choy / Asian greens | – | Apr 9–23 (sow outdoors) | Aug 13–27 (sowing) |
| Arugula | – | Apr 9–May 7 (sow outdoors) | Aug 13–Sep 10 (sowing) |
| Mustard greens | – | Apr 9–30 (sow outdoors) | Aug 13–27 (sowing) |
| Swiss chard | Mar 26–Apr 9 | Apr 23–May 14 (transplant) Apr 23–May 21 (sow outdoors) | Jul 30–Aug 13 (sowing) |
| Beet | – | Apr 9–May 7 (sow outdoors) | Jul 30–Aug 13 (sowing) |
| Carrot | – | Apr 16–May 14 (sow outdoors) | Jul 16–30 (sowing) |
| Radish | – | Apr 2–May 14 (sow outdoors) | Aug 27–Sep 10 (sowing) |
| Turnip | – | Apr 9–30 (sow outdoors) | Jul 30–Aug 13 (sowing) |
| Parsnip | – | Apr 16–May 7 (sow outdoors) | – |
| Pea (garden, snap, snow) | – | Mar 12–Apr 9 (sow outdoors) | Jul 16–30 (sowing) |
| Onion (bulbing) | Feb 12–26 | Mar 26–Apr 9 (transplant) | – |
| Green onion / scallion | – | Mar 26–Apr 23 (sow outdoors) | Jul 30–Aug 13 (sowing) |
| Leek | Feb 12–26 | Apr 9–23 (transplant) | – |
| Garlic | – | – | Aug 27–Sep 24 (sowing) |
| Shallot | – | Mar 26–Apr 9 (transplant) | Aug 27–Sep 24 (sowing) |
| Potato | – | Apr 9–23 (transplant) | Jun 18–Jul 2 (transplant) |
| Sweet potato | – | May 28–Jun 11 (transplant) | – |
| Sweet corn | – | May 14–28 (sow outdoors) | – |
| Bean, bush (snap) | – | May 14–28 (sow outdoors) | – |
| Bean, pole | – | May 14–28 (sow outdoors) | – |
| Lima bean | – | May 21–Jun 4 (sow outdoors) | – |
| Southern pea (cowpea, black-eyed pea) | – | May 28–Jun 18 (sow outdoors) | – |
| Cucumber | Apr 9–16 | May 14–28 (transplant) May 14–28 (sow outdoors) | – |
| Summer squash / zucchini | Apr 9–16 | May 14–28 (transplant) May 14–28 (sow outdoors) | – |
| Winter squash | Apr 9–16 | May 14–28 (transplant) May 14–28 (sow outdoors) | – |
| Pumpkin | – | May 14–28 (sow outdoors) | – |
| Watermelon | Apr 9–16 | May 21–Jun 4 (transplant) May 21–Jun 4 (sow outdoors) | – |
| Cantaloupe / muskmelon | Apr 9–16 | May 21–Jun 4 (transplant) May 21–Jun 4 (sow outdoors) | – |
| Okra | Mar 26–Apr 9 | May 21–Jun 4 (transplant) May 21–Jun 4 (sow outdoors) | – |
| Celery | Feb 12–26 | May 14–21 (transplant) | – |
| Basil | Mar 26–Apr 9 | May 14–28 (transplant) May 14–28 (sow outdoors) | – |
| Cilantro | – | Apr 23–May 21 (sow outdoors) | Aug 13–27 (sowing) |
| Parsley | Feb 26–Mar 12 | Apr 23–May 7 (transplant) Apr 16–May 7 (sow outdoors) | – |
| Dill | – | May 7–21 (sow outdoors) | Aug 13–27 (sowing) |
| Sunflower | – | May 7–21 (sow outdoors) | – |
| Asparagus (crowns) | – | Apr 9–23 (transplant) | – |
| Rhubarb (crowns) | – | Apr 9–23 (transplant) | – |
| Strawberry (plants) | – | Apr 9–23 (transplant) | Jul 30–Aug 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 May 7 here (the average last frost). Not affiliated with the program.
Where these numbers come from
Station: Cherry Creek Dam, CO (NOAA GHCN-Daily ID USC00051547), elevation 5,647 ft, 4.3 miles from the ZIP's center point. NOAA completeness flag: R (representative, 10+ years).
Nearby stations
| Station | Distance | Last frost (50%) | First frost (50%) |
|---|---|---|---|
| Denver-stapleton, CO | 6 mi | May 4 | Oct 8 |
| Denver Centennial AP, CO | 7 mi | May 5 | Oct 8 |
| Denver Water Dept, CO | 8 mi | Apr 30 | Oct 12 |
The average last-frost dates of these stations span 8 days, a rough guide to local variation. See data sources & methods.
Frost questions for 80231
When is the last frost in 80231?
The average (50% chance) last spring freeze of 32°F for ZIP 80231 is May 7. For a more cautious planting date, use May 21, when only 1 year in 10 still sees a later freeze.
When is the first frost in 80231?
The average first fall freeze is October 8. In 1 year in 10 it comes by September 25.
What hardiness zone is 80231?
ZIP 80231 is in USDA zone 6a (-10 to -5°F average coldest winter night), per the 2023 USDA Plant Hardiness Zone Map ZIP listing.
What is the soil temperature in 80231 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
80224 Denver 80247 Denver 80222 Denver 80237 Denver 80014 Aurora 80246 Denver 80012 Aurora 80230 Denver
Other ZIP codes in Denver County
80202 80203 80204 80205 80206 80207 80209 80210 80211 80212 80216 80218 80219 80220 80222 80223 80224 80230 80236 80237 80238 80239 80246 80247 All Denver County frost dates · Colorado frost dates
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