Clark, CO frost dates
Last spring frostJun 9median date
First fall frostSep 12median date
Growing season95 daysfrost-free
Hardiness zone5aZone 5a
How Clark compares
- In 8 years out of 10, the last spring frost in Clark falls between May 25 and June 24, a 30-day window. The first fall frost falls between August 31 and September 24.
- The median last frost is 29 days later than the Colorado median of May 11.
- Its 95-day growing season is longer than 12% of the 374 Colorado places with a regular frost season (state median 146 days).
- The last frost is 37 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 233 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 25 |
| 50% (median) | June 9 |
| 10% (safe for tender plants) | June 24 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | August 31 |
| 50% (median) | September 12 |
| 90% (late) | September 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 Clark, CO
Clark, CO frost dates — last frost Jun 9, first frost Sep 12, zone 5a. whenisthelastfrost.com
Crop
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Start indoors: Mar 17 to Mar 31Transplant outside: May 12 to May 26
Start indoors: Mar 31 to Apr 14Transplant outside: Jun 23 to Jul 7
Start indoors: Mar 31 to Apr 14Transplant outside: Jun 23 to Jul 7
Start indoors: Apr 14 to Apr 28Transplant outside: Jun 16 to Jun 30
Start indoors: Apr 14 to Apr 28Transplant outside: May 19 to Jun 2Sow outdoors: May 12 to Jun 16Plant for fall: Jul 18 to Aug 15
Start indoors: Apr 14 to Apr 28Transplant outside: May 12 to May 26Sow outdoors: May 12 to May 26Plant for fall: Jul 4 to Jul 25
Start indoors: Apr 14 to Apr 28Transplant outside: May 26 to Jun 9
Start indoors: Apr 14 to Apr 28Transplant outside: May 19 to Jun 2
Start indoors: Apr 14 to Apr 28Transplant outside: May 26 to Jun 9
Start indoors: Apr 28 to May 12Transplant outside: Jun 30 to Jul 14Sow outdoors: Jun 30 to Jul 14
Start indoors: Apr 28 to May 12Transplant outside: Jun 16 to Jun 30
Sow outdoors: Apr 28 to May 19
Sow outdoors: Apr 28 to May 19Plant for fall: Jul 18 to Aug 8
Sow outdoors: May 5 to Jun 16Plant for fall: Aug 1 to Aug 22
Start indoors: May 12 to May 19Transplant outside: Jun 23 to Jun 30Sow outdoors: Jun 16 to Jun 30
Start indoors: May 12 to May 19Sow outdoors: Jun 16 to Jun 30
Start indoors: May 12 to May 19Sow outdoors: Jun 16 to Jun 30
Start indoors: May 12 to May 19Transplant outside: Jun 23 to Jul 7
Sow outdoors: May 19 to Jun 16
Sow outdoors: May 19 to Jun 16Plant for fall: Jul 4 to Jul 18
Sow outdoors: May 19 to Jun 9
Sow outdoors: May 26 to Jun 23
Sow outdoors: May 26 to Jun 16Plant for fall: Jul 18 to Aug 8
Sow outdoors: Jun 16 to Jul 7
Sow outdoors: Jun 16 to Jun 30
Transplant outside: Jun 23 to Jul 14
Plant for fall: Aug 29 to Oct 3
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Clark, CO
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Mar 17 – Mar 31 | May 12 – May 26 | — | — |
| Peppers | Mar 31 – Apr 14 | Jun 23 – Jul 7 | — | — |
| Eggplant | Mar 31 – Apr 14 | Jun 23 – Jul 7 | — | — |
| Tomatoes | Apr 14 – Apr 28 | Jun 16 – Jun 30 | — | — |
| Lettuce | Apr 14 – Apr 28 | May 19 – Jun 2 | May 12 – Jun 16 | Jul 18 – Aug 15 |
| Kale | Apr 14 – Apr 28 | May 12 – May 26 | May 12 – May 26 | Jul 4 – Jul 25 |
| Broccoli | Apr 14 – Apr 28 | May 26 – Jun 9 | — | — |
| Cabbage | Apr 14 – Apr 28 | May 19 – Jun 2 | — | — |
| Cauliflower | Apr 14 – Apr 28 | May 26 – Jun 9 | — | — |
| Okra | Apr 28 – May 12 | Jun 30 – Jul 14 | Jun 30 – Jul 14 | — |
| Basil | Apr 28 – May 12 | Jun 16 – Jun 30 | — | — |
| Peas | — | — | Apr 28 – May 19 | — |
| Spinach | — | — | Apr 28 – May 19 | Jul 18 – Aug 8 |
| Radishes | — | — | May 5 – Jun 16 | Aug 1 – Aug 22 |
| Cucumbers | May 12 – May 19 | Jun 23 – Jun 30 | Jun 16 – Jun 30 | — |
| Zucchini & Summer Squash | May 12 – May 19 | — | Jun 16 – Jun 30 | — |
| Winter Squash & Pumpkins Warning: Your frost-free season is about 95 days, which is tight for winter squash & pumpkins (100+ days). Choose early varieties and use transplants or row covers. | May 12 – May 19 | — | Jun 16 – Jun 30 | — |
| Melons & Watermelon Warning: Your frost-free season is about 95 days, which is tight for melons & watermelon (85+ days). Choose early varieties and use transplants or row covers. | May 12 – May 19 | Jun 23 – Jul 7 | — | — |
| Carrots | — | — | May 19 – Jun 16 | — |
| Beets | — | — | May 19 – Jun 16 | Jul 4 – Jul 18 |
| Potatoes | — | — | May 19 – Jun 9 | — |
| Swiss Chard | — | — | May 26 – Jun 23 | — |
| Cilantro | — | — | May 26 – Jun 16 | Jul 18 – Aug 8 |
| Green Beans | — | — | Jun 16 – Jul 7 | — |
| Sweet Corn | — | — | Jun 16 – Jun 30 | — |
| Sweet Potatoes Warning: Your frost-free season is about 95 days, which is tight for sweet potatoes (100+ days). Choose early varieties and use transplants or row covers. | — | Jun 23 – Jul 14 | — | — |
| Garlic | — | — | — | Aug 29 – Oct 3 |
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 Steamboat Springs, CO weather station, 28 km away (elevation 6,867 ft (2,093 m)).
Frost dates near Clark
- Steamboat Springs Jun 9 · Sep 12
- Hayden Jun 1 · Sep 20
- Coalmont frost any month
- Slater Jun 1 · Sep 18
- Oak Creek Jun 14 · Sep 11
- Cowdrey frost any month
- Walden frost any month
- Craig Jun 6 · Sep 12
- Phippsburg Jun 14 · Sep 11
- Yampa Jun 14 · Sep 11
Frequently asked questions
When is the last frost in Clark, CO?
The median last spring frost in Clark, CO is June 9. There is still about a 10% chance of frost after June 24, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Clark, CO?
The median first fall frost is September 12, with about a 10% chance of frost before August 31.
How long is the growing season in Clark, CO?
About 95 days between the median last spring frost and first fall frost.
What planting zone is Clark, CO?
Clark, CO is in USDA hardiness zone 5a.