Delta, CO frost dates
Last spring frostMay 1median date
First fall frostOct 7median date
Growing season159 daysfrost-free
Hardiness zone6bZone 6b
How Delta compares
- In 8 years out of 10, the last spring frost in Delta falls between April 19 and May 14, a 25-day window. The first fall frost falls between September 26 and October 19.
- The median last frost is 10 days earlier than the Colorado median of May 11.
- Its 159-day growing season is longer than 76% of the 374 Colorado places with a regular frost season (state median 146 days).
- The last frost is 9 days later than the zone 6b median of Apr 22. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 6b chart.
- The weather station records an average of 160 nights a year at or below 32°F.
- Compared with Grand Junction, CO, 55 km away, the last frost here is 8 days later than there and the growing season is 21 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 19 |
| 50% (median) | May 1 |
| 10% (safe for tender plants) | May 14 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 26 |
| 50% (median) | October 7 |
| 90% (late) | October 19 |
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 Delta, CO
Delta, CO frost dates — last frost May 1, first frost Oct 7, zone 6b. whenisthelastfrost.com
Crop
JFMAMJJASOND
Start indoors: Feb 6 to Feb 20Transplant outside: Apr 3 to Apr 17
Start indoors: Feb 20 to Mar 6Transplant outside: May 15 to May 29
Start indoors: Feb 20 to Mar 6Transplant outside: May 15 to May 29
Start indoors: Mar 6 to Mar 20Transplant outside: May 8 to May 22
Start indoors: Mar 6 to Mar 20Transplant outside: Apr 10 to Apr 24Sow outdoors: Apr 3 to May 8Plant for fall: Aug 12 to Sep 9
Start indoors: Mar 6 to Mar 20Transplant outside: Apr 3 to Apr 17Sow outdoors: Apr 3 to Apr 17Plant for fall: Jul 29 to Aug 19
Start indoors: Mar 6 to Mar 20Transplant outside: Apr 17 to May 1Plant for fall: Jul 1 to Jul 22
Start indoors: Mar 6 to Mar 20Transplant outside: Apr 10 to Apr 24Plant for fall: Jul 1 to Jul 22
Start indoors: Mar 6 to Mar 20Transplant outside: Apr 17 to May 1Plant for fall: Jul 1 to Jul 22
Start indoors: Mar 20 to Apr 3Transplant outside: May 22 to Jun 5Sow outdoors: May 22 to Jun 5
Start indoors: Mar 20 to Apr 3Transplant outside: May 8 to May 22
Sow outdoors: Mar 20 to Apr 10Plant for fall: Jul 15 to Aug 5
Sow outdoors: Mar 20 to Apr 10Plant for fall: Aug 12 to Sep 2
Sow outdoors: Mar 27 to May 8Plant for fall: Aug 26 to Sep 16
Start indoors: Apr 3 to Apr 10Transplant outside: May 15 to May 22Sow outdoors: May 8 to May 22Plant for fall: Jul 22 to Aug 5
Start indoors: Apr 3 to Apr 10Sow outdoors: May 8 to May 22Plant for fall: Jul 29 to Aug 12
Start indoors: Apr 3 to Apr 10Sow outdoors: May 8 to May 22
Start indoors: Apr 3 to Apr 10Transplant outside: May 15 to May 29
Sow outdoors: Apr 10 to May 8Plant for fall: Jul 15 to Jul 29
Sow outdoors: Apr 10 to May 8Plant for fall: Jul 29 to Aug 12
Sow outdoors: Apr 10 to May 1
Sow outdoors: Apr 17 to May 15Plant for fall: Jul 29 to Aug 12
Sow outdoors: Apr 17 to May 8Plant for fall: Aug 12 to Sep 2
Sow outdoors: May 8 to May 29Plant for fall: Jul 22 to Aug 5
Sow outdoors: May 8 to May 22
Transplant outside: May 15 to Jun 5
Plant for fall: Sep 23 to Oct 28
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Delta, CO
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 6 – Feb 20 | Apr 3 – Apr 17 | — | — |
| Peppers | Feb 20 – Mar 6 | May 15 – May 29 | — | — |
| Eggplant | Feb 20 – Mar 6 | May 15 – May 29 | — | — |
| Tomatoes | Mar 6 – Mar 20 | May 8 – May 22 | — | — |
| Lettuce | Mar 6 – Mar 20 | Apr 10 – Apr 24 | Apr 3 – May 8 | Aug 12 – Sep 9 |
| Kale | Mar 6 – Mar 20 | Apr 3 – Apr 17 | Apr 3 – Apr 17 | Jul 29 – Aug 19 |
| Broccoli | Mar 6 – Mar 20 | Apr 17 – May 1 | — | Jul 1 – Jul 22 |
| Cabbage | Mar 6 – Mar 20 | Apr 10 – Apr 24 | — | Jul 1 – Jul 22 |
| Cauliflower | Mar 6 – Mar 20 | Apr 17 – May 1 | — | Jul 1 – Jul 22 |
| Okra | Mar 20 – Apr 3 | May 22 – Jun 5 | May 22 – Jun 5 | — |
| Basil | Mar 20 – Apr 3 | May 8 – May 22 | — | — |
| Peas | — | — | Mar 20 – Apr 10 | Jul 15 – Aug 5 |
| Spinach | — | — | Mar 20 – Apr 10 | Aug 12 – Sep 2 |
| Radishes | — | — | Mar 27 – May 8 | Aug 26 – Sep 16 |
| Cucumbers | Apr 3 – Apr 10 | May 15 – May 22 | May 8 – May 22 | Jul 22 – Aug 5 |
| Zucchini & Summer Squash | Apr 3 – Apr 10 | — | May 8 – May 22 | Jul 29 – Aug 12 |
| Winter Squash & Pumpkins | Apr 3 – Apr 10 | — | May 8 – May 22 | — |
| Melons & Watermelon | Apr 3 – Apr 10 | May 15 – May 29 | — | — |
| Carrots | — | — | Apr 10 – May 8 | Jul 15 – Jul 29 |
| Beets | — | — | Apr 10 – May 8 | Jul 29 – Aug 12 |
| Potatoes | — | — | Apr 10 – May 1 | — |
| Swiss Chard | — | — | Apr 17 – May 15 | Jul 29 – Aug 12 |
| Cilantro | — | — | Apr 17 – May 8 | Aug 12 – Sep 2 |
| Green Beans | — | — | May 8 – May 29 | Jul 22 – Aug 5 |
| Sweet Corn | — | — | May 8 – May 22 | — |
| Sweet Potatoes | — | May 15 – Jun 5 | — | — |
| Garlic | — | — | — | Sep 23 – Oct 28 |
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 Delta 3e, CO weather station, 3 km away (elevation 5,026 ft (1,532 m)).
Frost dates near Delta
- Cory May 1 · Oct 7
- Austin May 1 · Oct 7
- Eckert May 3 · Oct 9
- Olathe May 2 · Oct 8
- Cedaredge May 3 · Oct 9
- Lazear May 3 · Oct 12
- Hotchkiss May 3 · Oct 12
- Montrose Apr 28 · Oct 14
- Crawford May 23 · Oct 1
- Whitewater Apr 23 · Oct 20
Frequently asked questions
When is the last frost in Delta, CO?
The median last spring frost in Delta, CO is May 1. 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 Delta, CO?
The median first fall frost is October 7, with about a 10% chance of frost before September 26.
How long is the growing season in Delta, CO?
About 159 days between the median last spring frost and first fall frost.
What planting zone is Delta, CO?
Delta, CO is in USDA hardiness zone 6b.