Frost dates for 80221 — Denver, CO
How Denver compares
- In 8 years out of 10, the last spring frost in Denver falls between April 18 and May 14, a 26-day window. The first fall frost falls between September 26 and October 24.
- The median last frost is 9 days earlier than the Colorado median of May 11.
- Its 162-day growing season is longer than 85% of the 374 Colorado places with a regular frost season (state median 146 days).
- The last frost is typical for zone 6a, where the median is Apr 29.
- The weather station records an average of 149 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 18 |
| 50% (median) | May 2 |
| 10% (safe for tender plants) | May 14 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 26 |
| 50% (median) | October 11 |
| 90% (late) | October 24 |
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 80221 — Denver, CO — last frost May 2, first frost Oct 11, zone 6a. whenisthelastfrost.com
When to plant vegetables in Denver, CO
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 7 – Feb 21 | Apr 4 – Apr 18 | — | — |
| Peppers | Feb 21 – Mar 7 | May 16 – May 30 | — | — |
| Eggplant | Feb 21 – Mar 7 | May 16 – May 30 | — | — |
| Tomatoes | Mar 7 – Mar 21 | May 9 – May 23 | — | — |
| Lettuce | Mar 7 – Mar 21 | Apr 11 – Apr 25 | Apr 4 – May 9 | Aug 16 – Sep 13 |
| Kale | Mar 7 – Mar 21 | Apr 4 – Apr 18 | Apr 4 – Apr 18 | Aug 2 – Aug 23 |
| Broccoli | Mar 7 – Mar 21 | Apr 18 – May 2 | — | Jul 5 – Jul 26 |
| Cabbage | Mar 7 – Mar 21 | Apr 11 – Apr 25 | — | Jul 5 – Jul 26 |
| Cauliflower | Mar 7 – Mar 21 | Apr 18 – May 2 | — | Jul 5 – Jul 26 |
| Okra | Mar 21 – Apr 4 | May 23 – Jun 6 | May 23 – Jun 6 | — |
| Basil | Mar 21 – Apr 4 | May 9 – May 23 | — | — |
| Peas | — | — | Mar 21 – Apr 11 | Jul 19 – Aug 9 |
| Spinach | — | — | Mar 21 – Apr 11 | Aug 16 – Sep 6 |
| Radishes | — | — | Mar 28 – May 9 | Aug 30 – Sep 20 |
| Cucumbers | Apr 4 – Apr 11 | May 16 – May 23 | May 9 – May 23 | Jul 26 – Aug 9 |
| Zucchini & Summer Squash | Apr 4 – Apr 11 | — | May 9 – May 23 | Aug 2 – Aug 16 |
| Winter Squash & Pumpkins | Apr 4 – Apr 11 | — | May 9 – May 23 | — |
| Melons & Watermelon | Apr 4 – Apr 11 | May 16 – May 30 | — | — |
| Carrots | — | — | Apr 11 – May 9 | Jul 19 – Aug 2 |
| Beets | — | — | Apr 11 – May 9 | Aug 2 – Aug 16 |
| Potatoes | — | — | Apr 11 – May 2 | — |
| Swiss Chard | — | — | Apr 18 – May 16 | Aug 2 – Aug 16 |
| Cilantro | — | — | Apr 18 – May 9 | Aug 16 – Sep 6 |
| Green Beans | — | — | May 9 – May 30 | Jul 26 – Aug 9 |
| Sweet Corn | — | — | May 9 – May 23 | — |
| Sweet Potatoes | — | May 16 – Jun 6 | — | — |
| Garlic | — | — | — | Sep 27 – Nov 1 |
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 Northglenn, CO weather station, 7 km away (elevation 5,407 ft (1,648 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
- Westminster May 2 · Oct 11
- Thornton May 2 · Oct 11
- Dupont May 4 · Oct 8
- Commerce City May 4 · Oct 8
- Arvada May 5 · Oct 5
- Eastlake May 2 · Oct 11
- Wheat Ridge May 5 · Oct 5
- Broomfield 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 2. There is still about a 10% chance of frost after May 14, 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 11, with about a 10% chance of frost before September 26.
How long is the growing season in Denver, CO?
About 162 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.