Last spring frost
Jun 4
Frost Dates for Mancos, CO
First fall frost
Sep 24
Growing season
111 days
Hardiness zone
6a
In an average year around Mancos, CO, the last spring frost (32°F) is about Jun 4 and the first fall frost is about Sep 24, giving roughly a 111-day growing season. To be safe most years, wait until May 20 before setting out tender plants.
Last spring frost
Dates the last frost of spring typically ends. Plant tender crops after the risk has passed for your comfort level.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Jun 30 | Jun 15 | Jun 2 |
| Freeze (32°F) | Jun 19 | Jun 4 | May 20 |
| Hard (28°F) | Jun 9 | May 21 | May 5 |
| Severe (24°F) | May 24 | May 5 | Apr 23 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 30 | Jun 25 | Jun 21 | Jun 18 | Jun 15 | Jun 13 | Jun 9 | Jun 6 | Jun 2 |
| 32°F | Jun 19 | Jun 14 | Jun 11 | Jun 6 | Jun 4 | Jun 1 | May 29 | May 25 | May 20 |
| 28°F | Jun 9 | Jun 1 | May 28 | May 24 | May 21 | May 18 | May 15 | May 10 | May 5 |
| 24°F | May 24 | May 17 | May 13 | May 9 | May 5 | May 2 | Apr 30 | Apr 27 | Apr 23 |
| 20°F | May 10 | May 3 | Apr 30 | Apr 26 | Apr 23 | Apr 20 | Apr 15 | Apr 10 | Apr 3 |
| 16°F | Apr 27 | Apr 20 | Apr 16 | Apr 11 | Apr 7 | Apr 3 | Mar 31 | Mar 25 | Mar 16 |
First fall frost
Dates the first frost of fall typically arrives. Count back by a crop's days-to-maturity to know your planting cutoff.
| Frost intensity | Early (10%) | Average (50%) | Late (90%) |
|---|---|---|---|
| Light (36°F) | Sep 3 | Sep 15 | Sep 27 |
| Freeze (32°F) | Sep 9 | Sep 24 | Oct 4 |
| Hard (28°F) | Sep 17 | Oct 2 | Oct 15 |
| Severe (24°F) | Sep 26 | Oct 10 | Oct 26 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 3 | Sep 6 | Sep 9 | Sep 12 | Sep 15 | Sep 18 | Sep 21 | Sep 24 | Sep 27 |
| 32°F | Sep 9 | Sep 13 | Sep 18 | Sep 21 | Sep 24 | Sep 26 | Sep 29 | Oct 1 | Oct 4 |
| 28°F | Sep 17 | Sep 23 | Sep 27 | Sep 30 | Oct 2 | Oct 4 | Oct 6 | Oct 10 | Oct 15 |
| 24°F | Sep 26 | Oct 1 | Oct 4 | Oct 7 | Oct 10 | Oct 13 | Oct 17 | Oct 21 | Oct 26 |
| 20°F | Oct 5 | Oct 10 | Oct 14 | Oct 18 | Oct 21 | Oct 24 | Oct 28 | Nov 1 | Nov 5 |
| 16°F | Oct 16 | Oct 21 | Oct 25 | Oct 29 | Nov 1 | Nov 4 | Nov 7 | Nov 12 | Nov 18 |
Growing season is measured at 32°F with about 50% probability. Hardiness zone from the 2023 USDA map; frost normals from NOAA 1991-2020.
Where this data comes from
@endif These dates are computed from the nearest official weather station with long-term records: Mancos 1Sw, Co, about 4.5 miles away@if(!empty($station['elevation_ft'])), at 6,897 ft elevation. The further the station and the greater the elevation difference from your yard, the more your local frost timing can vary.
How we calculate these dates
Frost and freeze dates come from the NOAA 1991–2020 U.S. Climate Normals, the National Oceanic and Atmospheric Administration's 30-year averages for each weather station. A date shown at the 50% level is the median: in half of years the frost falls on or before it. The 10% and 90% columns show the early and late ends of the range, so you can plant on the odds you're comfortable with. These are long-term averages, not a forecast for this year - always check your local outlook before planting.
Source: NOAA National Centers for Environmental Information, 1991–2020 Climate Normals (public domain). Harman is not affiliated with or endorsed by NOAA.
Frequently asked questions
When is the last frost in Mancos, CO?
On average, the last spring frost (32°F) around Mancos, CO is about Jun 4. In cooler years it can run later, so for a safer bet many gardeners wait until May 20.
When is the first frost in the fall?
The first fall frost around Mancos, CO typically arrives about Sep 24. Count back by a crop's days to maturity to find the latest date you can plant it.
When can I plant tomatoes and other tender crops?
Tender crops like tomatoes, peppers and basil are damaged by frost, so wait until the last spring frost has passed - around Jun 4 on average, or May 20 to be safe most years.
How long is the growing season here?
The frost-free growing season (between the last spring and first fall 32°F frost) is about 111 days in a typical year.
Are these dates a forecast for this year?
No. They are 30-year averages from the NOAA 1991–2020 Climate Normals, not a prediction for the current year. Use them for planning and always check your local weather forecast before planting or protecting crops.
Local weather for 81328 Planting calendar → Colorado frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026