Frost dates for 80239 — Denver, CO
How Denver compares
- In 8 years out of 10, the last spring frost in Denver falls between April 20 and May 16, a 26-day window. The first fall frost falls between September 25 and October 20.
- The median last frost is 7 days earlier than the Colorado median of May 11.
- Its 157-day growing season is longer than 69% of the 374 Colorado places with a regular frost season (state median 146 days).
- The last frost is 5 days later than the zone 6a median of Apr 29. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 6a chart.
- The weather station records an average of 156 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 20 |
| 50% (median) | May 4 |
| 10% (safe for tender plants) | May 16 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 25 |
| 50% (median) | October 8 |
| 90% (late) | October 20 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Denver, CO
Frost dates for 80239 — Denver, CO — last frost May 4, first frost Oct 8, zone 6a. whenisthelastfrost.com
When to plant vegetables in Denver, CO
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 9 – Feb 23 | Apr 6 – Apr 20 | — | — |
| Peppers | Feb 23 – Mar 9 | May 18 – Jun 1 | — | — |
| Eggplant | Feb 23 – Mar 9 | May 18 – Jun 1 | — | — |
| Tomatoes | Mar 9 – Mar 23 | May 11 – May 25 | — | — |
| Lettuce | Mar 9 – Mar 23 | Apr 13 – Apr 27 | Apr 6 – May 11 | Aug 13 – Sep 10 |
| Kale | Mar 9 – Mar 23 | Apr 6 – Apr 20 | Apr 6 – Apr 20 | Jul 30 – Aug 20 |
| Broccoli | Mar 9 – Mar 23 | Apr 20 – May 4 | — | Jul 2 – Jul 23 |
| Cabbage | Mar 9 – Mar 23 | Apr 13 – Apr 27 | — | Jul 2 – Jul 23 |
| Cauliflower | Mar 9 – Mar 23 | Apr 20 – May 4 | — | Jul 2 – Jul 23 |
| Okra | Mar 23 – Apr 6 | May 25 – Jun 8 | May 25 – Jun 8 | — |
| Basil | Mar 23 – Apr 6 | May 11 – May 25 | — | — |
| Peas | — | — | Mar 23 – Apr 13 | Jul 16 – Aug 6 |
| Spinach | — | — | Mar 23 – Apr 13 | Aug 13 – Sep 3 |
| Radishes | — | — | Mar 30 – May 11 | Aug 27 – Sep 17 |
| Cucumbers | Apr 6 – Apr 13 | May 18 – May 25 | May 11 – May 25 | Jul 23 – Aug 6 |
| Zucchini & Summer Squash | Apr 6 – Apr 13 | — | May 11 – May 25 | Jul 30 – Aug 13 |
| Winter Squash & Pumpkins | Apr 6 – Apr 13 | — | May 11 – May 25 | — |
| Melons & Watermelon | Apr 6 – Apr 13 | May 18 – Jun 1 | — | — |
| Carrots | — | — | Apr 13 – May 11 | Jul 16 – Jul 30 |
| Beets | — | — | Apr 13 – May 11 | Jul 30 – Aug 13 |
| Potatoes | — | — | Apr 13 – May 4 | — |
| Swiss Chard | — | — | Apr 20 – May 18 | Jul 30 – Aug 13 |
| Cilantro | — | — | Apr 20 – May 11 | Aug 13 – Sep 3 |
| Green Beans | — | — | May 11 – Jun 1 | Jul 23 – Aug 6 |
| Sweet Corn | — | — | May 11 – May 25 | — |
| Sweet Potatoes | — | May 18 – Jun 8 | — | — |
| Garlic | — | — | — | Sep 24 – Oct 29 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Denver-Stapleton, CO weather station, 4 km away (elevation 5,285 ft (1,611 m)).
ZIP codes in Denver: 80201 80202 80203 80204 80205 80206 80207 80208 80209 80210 80211 80212 80214 80215 80216 80217 80218 80219 80220 80221 80222 80223 80224 80225 80226 80227 80228 80229 80230 80231 80232 80233 80234 80235 80236 80237 80238 80239 80243 80244 80246 80247 80248 80249 80250 80251 80252 80256 80257 80259 80260 80261 80262 80263 80264 80265 80266 80271 80273 80274 …
Frost dates near Denver
- Commerce City May 4 · Oct 8
- Dupont May 4 · Oct 8
- Aurora May 7 · Oct 8
- Henderson May 3 · Oct 7
- Thornton May 2 · Oct 11
- Brighton May 3 · Oct 7
- Westminster May 2 · Oct 11
- Eastlake May 2 · Oct 11
Frequently asked questions
When is the last frost in Denver, CO?
The median last spring frost in Denver, CO is May 4. There is still about a 10% chance of frost after May 16, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Denver, CO?
The median first fall frost is October 8, with about a 10% chance of frost before September 25.
How long is the growing season in Denver, CO?
About 157 days between the median last spring frost and first fall frost.
What planting zone is Denver, CO?
Denver, CO is in USDA hardiness zone 6a.