Dupont, CO frost dates
Last spring frostMay 4median date
First fall frostOct 8median date
Growing season157 daysfrost-free
Hardiness zone6aZone 6a
How Dupont compares
- In 8 years out of 10, the last spring frost in Dupont 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.
- Dupont shares its weather station with Commerce City, CO, 3 km away, so the two have the same frost dates.
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 Dupont, CO
Dupont, CO frost dates — last frost May 4, first frost Oct 8, zone 6a. whenisthelastfrost.com
Crop
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Start indoors: Feb 9 to Feb 23Transplant outside: Apr 6 to Apr 20
Start indoors: Feb 23 to Mar 9Transplant outside: May 18 to Jun 1
Start indoors: Feb 23 to Mar 9Transplant outside: May 18 to Jun 1
Start indoors: Mar 9 to Mar 23Transplant outside: May 11 to May 25
Start indoors: Mar 9 to Mar 23Transplant outside: Apr 13 to Apr 27Sow outdoors: Apr 6 to May 11Plant for fall: Aug 13 to Sep 10
Start indoors: Mar 9 to Mar 23Transplant outside: Apr 6 to Apr 20Sow outdoors: Apr 6 to Apr 20Plant for fall: Jul 30 to Aug 20
Start indoors: Mar 9 to Mar 23Transplant outside: Apr 20 to May 4Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 9 to Mar 23Transplant outside: Apr 13 to Apr 27Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 9 to Mar 23Transplant outside: Apr 20 to May 4Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 23 to Apr 6Transplant outside: May 25 to Jun 8Sow outdoors: May 25 to Jun 8
Start indoors: Mar 23 to Apr 6Transplant outside: May 11 to May 25
Sow outdoors: Mar 23 to Apr 13Plant for fall: Jul 16 to Aug 6
Sow outdoors: Mar 23 to Apr 13Plant for fall: Aug 13 to Sep 3
Sow outdoors: Mar 30 to May 11Plant for fall: Aug 27 to Sep 17
Start indoors: Apr 6 to Apr 13Transplant outside: May 18 to May 25Sow outdoors: May 11 to May 25Plant for fall: Jul 23 to Aug 6
Start indoors: Apr 6 to Apr 13Sow outdoors: May 11 to May 25Plant for fall: Jul 30 to Aug 13
Start indoors: Apr 6 to Apr 13Sow outdoors: May 11 to May 25
Start indoors: Apr 6 to Apr 13Transplant outside: May 18 to Jun 1
Sow outdoors: Apr 13 to May 11Plant for fall: Jul 16 to Jul 30
Sow outdoors: Apr 13 to May 11Plant for fall: Jul 30 to Aug 13
Sow outdoors: Apr 13 to May 4
Sow outdoors: Apr 20 to May 18Plant for fall: Jul 30 to Aug 13
Sow outdoors: Apr 20 to May 11Plant for fall: Aug 13 to Sep 3
Sow outdoors: May 11 to Jun 1Plant for fall: Jul 23 to Aug 6
Sow outdoors: May 11 to May 25
Transplant outside: May 18 to Jun 8
Plant for fall: Sep 24 to Oct 29
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Dupont, 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, 10 km away (elevation 5,285 ft (1,611 m)).
Frost dates near Dupont
- Commerce City May 4 · Oct 8
- Thornton May 2 · Oct 11
- Henderson May 3 · Oct 7
- Eastlake May 2 · Oct 11
- Westminster May 2 · Oct 11
- Denver Apr 30 · Oct 12
- Brighton May 3 · Oct 7
- Broomfield May 2 · Oct 11
- Arvada May 5 · Oct 5
- Wheat Ridge May 5 · Oct 5
Frequently asked questions
When is the last frost in Dupont, CO?
The median last spring frost in Dupont, 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 Dupont, 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 Dupont, CO?
About 157 days between the median last spring frost and first fall frost.
What planting zone is Dupont, CO?
Dupont, CO is in USDA hardiness zone 6a.