Frost dates for 81611 — Aspen, CO
Last spring frostJun 2median date
First fall frostSep 23median date
Growing season113 daysfrost-free
Hardiness zone5aZone 5a
How Aspen compares
- In 8 years out of 10, the last spring frost in Aspen falls between May 17 and June 17, a 31-day window. The first fall frost falls between September 12 and October 4.
- The median last frost is 22 days later than the Colorado median of May 11.
- Its 113-day growing season is longer than 21% of the 374 Colorado places with a regular frost season (state median 146 days).
- The last frost is 30 days later than the zone 5a median of May 3. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 5a chart.
- The weather station records an average of 210 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 17 |
| 50% (median) | June 2 |
| 10% (safe for tender plants) | June 17 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 12 |
| 50% (median) | September 23 |
| 90% (late) | October 4 |
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 Aspen, CO
Frost dates for 81611 — Aspen, CO — last frost Jun 2, first frost Sep 23, zone 5a. whenisthelastfrost.com
Crop
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Start indoors: Mar 10 to Mar 24Transplant outside: May 5 to May 19
Start indoors: Mar 24 to Apr 7Transplant outside: Jun 16 to Jun 30
Start indoors: Mar 24 to Apr 7Transplant outside: Jun 16 to Jun 30
Start indoors: Apr 7 to Apr 21Transplant outside: Jun 9 to Jun 23
Start indoors: Apr 7 to Apr 21Transplant outside: May 12 to May 26Sow outdoors: May 5 to Jun 9Plant for fall: Jul 29 to Aug 26
Start indoors: Apr 7 to Apr 21Transplant outside: May 5 to May 19Sow outdoors: May 5 to May 19Plant for fall: Jul 15 to Aug 5
Start indoors: Apr 7 to Apr 21Transplant outside: May 19 to Jun 2Plant for fall: Jun 17 to Jul 8
Start indoors: Apr 7 to Apr 21Transplant outside: May 12 to May 26Plant for fall: Jun 17 to Jul 8
Start indoors: Apr 7 to Apr 21Transplant outside: May 19 to Jun 2Plant for fall: Jun 17 to Jul 8
Start indoors: Apr 21 to May 5Transplant outside: Jun 23 to Jul 7Sow outdoors: Jun 23 to Jul 7
Start indoors: Apr 21 to May 5Transplant outside: Jun 9 to Jun 23
Sow outdoors: Apr 21 to May 12Plant for fall: Jul 1 to Jul 22
Sow outdoors: Apr 21 to May 12Plant for fall: Jul 29 to Aug 19
Sow outdoors: Apr 28 to Jun 9Plant for fall: Aug 12 to Sep 2
Start indoors: May 5 to May 12Transplant outside: Jun 16 to Jun 23Sow outdoors: Jun 9 to Jun 23Plant for fall: Jul 8 to Jul 22
Start indoors: May 5 to May 12Sow outdoors: Jun 9 to Jun 23Plant for fall: Jul 15 to Jul 29
Start indoors: May 5 to May 12Sow outdoors: Jun 9 to Jun 23
Start indoors: May 5 to May 12Transplant outside: Jun 16 to Jun 30
Sow outdoors: May 12 to Jun 9Plant for fall: Jul 1 to Jul 15
Sow outdoors: May 12 to Jun 9Plant for fall: Jul 15 to Jul 29
Sow outdoors: May 12 to Jun 2
Sow outdoors: May 19 to Jun 16Plant for fall: Jul 15 to Jul 29
Sow outdoors: May 19 to Jun 9Plant for fall: Jul 29 to Aug 19
Sow outdoors: Jun 9 to Jun 30
Sow outdoors: Jun 9 to Jun 23
Transplant outside: Jun 16 to Jul 7
Plant for fall: Sep 9 to Oct 14
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Aspen, CO
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 10 – Mar 24 | May 5 – May 19 | — | — |
| Peppers | Mar 24 – Apr 7 | Jun 16 – Jun 30 | — | — |
| Eggplant | Mar 24 – Apr 7 | Jun 16 – Jun 30 | — | — |
| Tomatoes | Apr 7 – Apr 21 | Jun 9 – Jun 23 | — | — |
| Lettuce | Apr 7 – Apr 21 | May 12 – May 26 | May 5 – Jun 9 | Jul 29 – Aug 26 |
| Kale | Apr 7 – Apr 21 | May 5 – May 19 | May 5 – May 19 | Jul 15 – Aug 5 |
| Broccoli | Apr 7 – Apr 21 | May 19 – Jun 2 | — | Jun 17 – Jul 8 |
| Cabbage | Apr 7 – Apr 21 | May 12 – May 26 | — | Jun 17 – Jul 8 |
| Cauliflower | Apr 7 – Apr 21 | May 19 – Jun 2 | — | Jun 17 – Jul 8 |
| Okra | Apr 21 – May 5 | Jun 23 – Jul 7 | Jun 23 – Jul 7 | — |
| Basil | Apr 21 – May 5 | Jun 9 – Jun 23 | — | — |
| Peas | — | — | Apr 21 – May 12 | Jul 1 – Jul 22 |
| Spinach | — | — | Apr 21 – May 12 | Jul 29 – Aug 19 |
| Radishes | — | — | Apr 28 – Jun 9 | Aug 12 – Sep 2 |
| Cucumbers | May 5 – May 12 | Jun 16 – Jun 23 | Jun 9 – Jun 23 | Jul 8 – Jul 22 |
| Zucchini & Summer Squash | May 5 – May 12 | — | Jun 9 – Jun 23 | Jul 15 – Jul 29 |
| Winter Squash & Pumpkins Warning: Your frost-free season is about 113 days, which is tight for winter squash & pumpkins (100+ days). Choose early varieties and use transplants or row covers. | May 5 – May 12 | — | Jun 9 – Jun 23 | — |
| Melons & Watermelon | May 5 – May 12 | Jun 16 – Jun 30 | — | — |
| Carrots | — | — | May 12 – Jun 9 | Jul 1 – Jul 15 |
| Beets | — | — | May 12 – Jun 9 | Jul 15 – Jul 29 |
| Potatoes | — | — | May 12 – Jun 2 | — |
| Swiss Chard | — | — | May 19 – Jun 16 | Jul 15 – Jul 29 |
| Cilantro | — | — | May 19 – Jun 9 | Jul 29 – Aug 19 |
| Green Beans | — | — | Jun 9 – Jun 30 | — |
| Sweet Corn | — | — | Jun 9 – Jun 23 | — |
| Sweet Potatoes Warning: Your frost-free season is about 113 days, which is tight for sweet potatoes (100+ days). Choose early varieties and use transplants or row covers. | — | Jun 16 – Jul 7 | — | — |
| Garlic | — | — | — | Sep 9 – Oct 14 |
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 Aspen 1sw, CO weather station, 2 km away (elevation 8,176 ft (2,492 m)).
ZIP codes in Aspen: 81611 81612
Frost dates near Aspen
- Snowmass Village May 31 · Sep 23
- Woody Creek May 31 · Sep 23
- Snowmass May 31 · Sep 23
- Meredith frost any month
- Basalt May 31 · Sep 23
- Carbondale May 31 · Sep 23
- Twin Lakes Jun 16 · Sep 10
- Crested Butte frost any month
Frequently asked questions
When is the last frost in Aspen, CO?
The median last spring frost in Aspen, CO is June 2. There is still about a 10% chance of frost after June 17, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Aspen, CO?
The median first fall frost is September 23, with about a 10% chance of frost before September 12.
How long is the growing season in Aspen, CO?
About 113 days between the median last spring frost and first fall frost.
What planting zone is Aspen, CO?
Aspen, CO is in USDA hardiness zone 5a.