Silt, CO frost dates
Last spring frostMay 11median date
First fall frostOct 4median date
Growing season146 daysfrost-free
Hardiness zone6aZone 6a
How Silt compares
- In 8 years out of 10, the last spring frost in Silt falls between April 28 and May 27, a 29-day window. The first fall frost falls between September 23 and October 17.
- The median last frost is the same as the Colorado median of May 11.
- Its 146-day growing season is longer than 50% of the 374 Colorado places with a regular frost season (state median 146 days).
- The last frost is 12 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 173 nights a year at or below 32°F.
- Compared with Grand Junction, CO, 89 km away, the last frost here is 18 days later than there and the growing season is 34 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 28 |
| 50% (median) | May 11 |
| 10% (safe for tender plants) | May 27 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 23 |
| 50% (median) | October 4 |
| 90% (late) | October 17 |
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 Silt, CO
Silt, CO frost dates — last frost May 11, first frost Oct 4, zone 6a. whenisthelastfrost.com
Crop
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Start indoors: Feb 16 to Mar 2Transplant outside: Apr 13 to Apr 27
Start indoors: Mar 2 to Mar 16Transplant outside: May 25 to Jun 8
Start indoors: Mar 2 to Mar 16Transplant outside: May 25 to Jun 8
Start indoors: Mar 16 to Mar 30Transplant outside: May 18 to Jun 1
Start indoors: Mar 16 to Mar 30Transplant outside: Apr 20 to May 4Sow outdoors: Apr 13 to May 18Plant for fall: Aug 9 to Sep 6
Start indoors: Mar 16 to Mar 30Transplant outside: Apr 13 to Apr 27Sow outdoors: Apr 13 to Apr 27Plant for fall: Jul 26 to Aug 16
Start indoors: Mar 16 to Mar 30Transplant outside: Apr 27 to May 11Plant for fall: Jun 28 to Jul 19
Start indoors: Mar 16 to Mar 30Transplant outside: Apr 20 to May 4Plant for fall: Jun 28 to Jul 19
Start indoors: Mar 16 to Mar 30Transplant outside: Apr 27 to May 11Plant for fall: Jun 28 to Jul 19
Start indoors: Mar 30 to Apr 13Transplant outside: Jun 1 to Jun 15Sow outdoors: Jun 1 to Jun 15
Start indoors: Mar 30 to Apr 13Transplant outside: May 18 to Jun 1
Sow outdoors: Mar 30 to Apr 20Plant for fall: Jul 12 to Aug 2
Sow outdoors: Mar 30 to Apr 20Plant for fall: Aug 9 to Aug 30
Sow outdoors: Apr 6 to May 18Plant for fall: Aug 23 to Sep 13
Start indoors: Apr 13 to Apr 20Transplant outside: May 25 to Jun 1Sow outdoors: May 18 to Jun 1Plant for fall: Jul 19 to Aug 2
Start indoors: Apr 13 to Apr 20Sow outdoors: May 18 to Jun 1Plant for fall: Jul 26 to Aug 9
Start indoors: Apr 13 to Apr 20Sow outdoors: May 18 to Jun 1
Start indoors: Apr 13 to Apr 20Transplant outside: May 25 to Jun 8
Sow outdoors: Apr 20 to May 18Plant for fall: Jul 12 to Jul 26
Sow outdoors: Apr 20 to May 18Plant for fall: Jul 26 to Aug 9
Sow outdoors: Apr 20 to May 11
Sow outdoors: Apr 27 to May 25Plant for fall: Jul 26 to Aug 9
Sow outdoors: Apr 27 to May 18Plant for fall: Aug 9 to Aug 30
Sow outdoors: May 18 to Jun 8Plant for fall: Jul 19 to Aug 2
Sow outdoors: May 18 to Jun 1
Transplant outside: May 25 to Jun 15
Plant for fall: Sep 20 to Oct 25
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Silt, CO
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 16 – Mar 2 | Apr 13 – Apr 27 | — | — |
| Peppers | Mar 2 – Mar 16 | May 25 – Jun 8 | — | — |
| Eggplant | Mar 2 – Mar 16 | May 25 – Jun 8 | — | — |
| Tomatoes | Mar 16 – Mar 30 | May 18 – Jun 1 | — | — |
| Lettuce | Mar 16 – Mar 30 | Apr 20 – May 4 | Apr 13 – May 18 | Aug 9 – Sep 6 |
| Kale | Mar 16 – Mar 30 | Apr 13 – Apr 27 | Apr 13 – Apr 27 | Jul 26 – Aug 16 |
| Broccoli | Mar 16 – Mar 30 | Apr 27 – May 11 | — | Jun 28 – Jul 19 |
| Cabbage | Mar 16 – Mar 30 | Apr 20 – May 4 | — | Jun 28 – Jul 19 |
| Cauliflower | Mar 16 – Mar 30 | Apr 27 – May 11 | — | Jun 28 – Jul 19 |
| Okra | Mar 30 – Apr 13 | Jun 1 – Jun 15 | Jun 1 – Jun 15 | — |
| Basil | Mar 30 – Apr 13 | May 18 – Jun 1 | — | — |
| Peas | — | — | Mar 30 – Apr 20 | Jul 12 – Aug 2 |
| Spinach | — | — | Mar 30 – Apr 20 | Aug 9 – Aug 30 |
| Radishes | — | — | Apr 6 – May 18 | Aug 23 – Sep 13 |
| Cucumbers | Apr 13 – Apr 20 | May 25 – Jun 1 | May 18 – Jun 1 | Jul 19 – Aug 2 |
| Zucchini & Summer Squash | Apr 13 – Apr 20 | — | May 18 – Jun 1 | Jul 26 – Aug 9 |
| Winter Squash & Pumpkins | Apr 13 – Apr 20 | — | May 18 – Jun 1 | — |
| Melons & Watermelon | Apr 13 – Apr 20 | May 25 – Jun 8 | — | — |
| Carrots | — | — | Apr 20 – May 18 | Jul 12 – Jul 26 |
| Beets | — | — | Apr 20 – May 18 | Jul 26 – Aug 9 |
| Potatoes | — | — | Apr 20 – May 11 | — |
| Swiss Chard | — | — | Apr 27 – May 25 | Jul 26 – Aug 9 |
| Cilantro | — | — | Apr 27 – May 18 | Aug 9 – Aug 30 |
| Green Beans | — | — | May 18 – Jun 8 | Jul 19 – Aug 2 |
| Sweet Corn | — | — | May 18 – Jun 1 | — |
| Sweet Potatoes | — | May 25 – Jun 15 | — | — |
| Garlic | — | — | — | Sep 20 – Oct 25 |
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 Rifle Garfield Co Ap, CO weather station, 6 km away (elevation 5,531 ft (1,686 m)).
Frost dates near Silt
- Rifle May 23 · Sep 25
- New Castle May 23 · Sep 25
- Glenwood Springs May 13 · Oct 3
- Battlement Mesa May 17 · Sep 30
- Parachute May 17 · Sep 30
- Collbran May 17 · Sep 30
- Carbondale May 31 · Sep 23
- Molina May 17 · Sep 30
- De Beque May 17 · Sep 30
- Mesa May 17 · Sep 30
Frequently asked questions
When is the last frost in Silt, CO?
The median last spring frost in Silt, CO is May 11. There is still about a 10% chance of frost after May 27, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Silt, CO?
The median first fall frost is October 4, with about a 10% chance of frost before September 23.
How long is the growing season in Silt, CO?
About 146 days between the median last spring frost and first fall frost.
What planting zone is Silt, CO?
Silt, CO is in USDA hardiness zone 6a.