Mack, CO frost dates
Last spring frostApr 27median date
First fall frostOct 11median date
Growing season167 daysfrost-free
Hardiness zone7aZone 7a
How Mack compares
- In 8 years out of 10, the last spring frost in Mack falls between April 17 and May 7, a 20-day window. The first fall frost falls between September 28 and October 25.
- The median last frost is 14 days earlier than the Colorado median of May 11.
- Its 167-day growing season is longer than 95% of the 374 Colorado places with a regular frost season (state median 146 days).
- The last frost is 11 days later than the zone 7a median of Apr 16. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 7a chart.
- The weather station records an average of 167 nights a year at or below 32°F.
- Compared with Grand Junction, CO, 41 km away, the last frost here is 4 days later than there and the growing season is 13 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 17 |
| 50% (median) | April 27 |
| 10% (safe for tender plants) | May 7 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 28 |
| 50% (median) | October 11 |
| 90% (late) | October 25 |
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 Mack, CO
Mack, CO frost dates — last frost Apr 27, first frost Oct 11, zone 7a. whenisthelastfrost.com
Crop
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Start indoors: Feb 2 to Feb 16Transplant outside: Mar 30 to Apr 13
Start indoors: Feb 16 to Mar 2Transplant outside: May 11 to May 25
Start indoors: Feb 16 to Mar 2Transplant outside: May 11 to May 25
Start indoors: Mar 2 to Mar 16Transplant outside: May 4 to May 18
Start indoors: Mar 2 to Mar 16Transplant outside: Apr 6 to Apr 20Sow outdoors: Mar 30 to May 4Plant for fall: Aug 16 to Sep 13
Start indoors: Mar 2 to Mar 16Transplant outside: Mar 30 to Apr 13Sow outdoors: Mar 30 to Apr 13Plant for fall: Aug 2 to Aug 23
Start indoors: Mar 2 to Mar 16Transplant outside: Apr 13 to Apr 27Plant for fall: Jul 5 to Jul 26
Start indoors: Mar 2 to Mar 16Transplant outside: Apr 6 to Apr 20Plant for fall: Jul 5 to Jul 26
Start indoors: Mar 2 to Mar 16Transplant outside: Apr 13 to Apr 27Plant for fall: Jul 5 to Jul 26
Start indoors: Mar 16 to Mar 30Transplant outside: May 18 to Jun 1Sow outdoors: May 18 to Jun 1
Start indoors: Mar 16 to Mar 30Transplant outside: May 4 to May 18
Sow outdoors: Mar 16 to Apr 6Plant for fall: Jul 19 to Aug 9
Sow outdoors: Mar 16 to Apr 6Plant for fall: Aug 16 to Sep 6
Sow outdoors: Mar 23 to May 4Plant for fall: Aug 30 to Sep 20
Start indoors: Mar 30 to Apr 6Transplant outside: May 11 to May 18Sow outdoors: May 4 to May 18Plant for fall: Jul 26 to Aug 9
Start indoors: Mar 30 to Apr 6Sow outdoors: May 4 to May 18Plant for fall: Aug 2 to Aug 16
Start indoors: Mar 30 to Apr 6Sow outdoors: May 4 to May 18
Start indoors: Mar 30 to Apr 6Transplant outside: May 11 to May 25
Sow outdoors: Apr 6 to May 4Plant for fall: Jul 19 to Aug 2
Sow outdoors: Apr 6 to May 4Plant for fall: Aug 2 to Aug 16
Sow outdoors: Apr 6 to Apr 27
Sow outdoors: Apr 13 to May 11Plant for fall: Aug 2 to Aug 16
Sow outdoors: Apr 13 to May 4Plant for fall: Aug 16 to Sep 6
Sow outdoors: May 4 to May 25Plant for fall: Jul 26 to Aug 9
Sow outdoors: May 4 to May 18
Transplant outside: May 11 to Jun 1
Plant for fall: Sep 27 to Nov 1
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Mack, CO
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 2 – Feb 16 | Mar 30 – Apr 13 | — | — |
| Peppers | Feb 16 – Mar 2 | May 11 – May 25 | — | — |
| Eggplant | Feb 16 – Mar 2 | May 11 – May 25 | — | — |
| Tomatoes | Mar 2 – Mar 16 | May 4 – May 18 | — | — |
| Lettuce | Mar 2 – Mar 16 | Apr 6 – Apr 20 | Mar 30 – May 4 | Aug 16 – Sep 13 |
| Kale | Mar 2 – Mar 16 | Mar 30 – Apr 13 | Mar 30 – Apr 13 | Aug 2 – Aug 23 |
| Broccoli | Mar 2 – Mar 16 | Apr 13 – Apr 27 | — | Jul 5 – Jul 26 |
| Cabbage | Mar 2 – Mar 16 | Apr 6 – Apr 20 | — | Jul 5 – Jul 26 |
| Cauliflower | Mar 2 – Mar 16 | Apr 13 – Apr 27 | — | Jul 5 – Jul 26 |
| Okra | Mar 16 – Mar 30 | May 18 – Jun 1 | May 18 – Jun 1 | — |
| Basil | Mar 16 – Mar 30 | May 4 – May 18 | — | — |
| Peas | — | — | Mar 16 – Apr 6 | Jul 19 – Aug 9 |
| Spinach | — | — | Mar 16 – Apr 6 | Aug 16 – Sep 6 |
| Radishes | — | — | Mar 23 – May 4 | Aug 30 – Sep 20 |
| Cucumbers | Mar 30 – Apr 6 | May 11 – May 18 | May 4 – May 18 | Jul 26 – Aug 9 |
| Zucchini & Summer Squash | Mar 30 – Apr 6 | — | May 4 – May 18 | Aug 2 – Aug 16 |
| Winter Squash & Pumpkins | Mar 30 – Apr 6 | — | May 4 – May 18 | — |
| Melons & Watermelon | Mar 30 – Apr 6 | May 11 – May 25 | — | — |
| Carrots | — | — | Apr 6 – May 4 | Jul 19 – Aug 2 |
| Beets | — | — | Apr 6 – May 4 | Aug 2 – Aug 16 |
| Potatoes | — | — | Apr 6 – Apr 27 | — |
| Swiss Chard | — | — | Apr 13 – May 11 | Aug 2 – Aug 16 |
| Cilantro | — | — | Apr 13 – May 4 | Aug 16 – Sep 6 |
| Green Beans | — | — | May 4 – May 25 | Jul 26 – Aug 9 |
| Sweet Corn | — | — | May 4 – May 18 | — |
| Sweet Potatoes | — | May 11 – Jun 1 | — | — |
| 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 Fruita, CO weather station, 21 km away (elevation 4,498 ft (1,371 m)).
Frost dates near Mack
- Loma Apr 27 · Oct 11
- Fruita Apr 27 · Oct 11
- Glade Park Apr 26 · Oct 16
- Grand Junction Apr 23 · Oct 20
- Clifton Apr 23 · Oct 20
- Palisade Apr 17 · Oct 26
- Whitewater Apr 23 · Oct 20
- De Beque May 17 · Sep 30
- Gateway Apr 20 · Oct 21
- Mesa May 17 · Sep 30
Frequently asked questions
When is the last frost in Mack, CO?
The median last spring frost in Mack, CO is April 27. There is still about a 10% chance of frost after May 7, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Mack, CO?
The median first fall frost is October 11, with about a 10% chance of frost before September 28.
How long is the growing season in Mack, CO?
About 167 days between the median last spring frost and first fall frost.
What planting zone is Mack, CO?
Mack, CO is in USDA hardiness zone 7a.