Last spring frost
Apr 17
Frost Dates for Clifton, CO
First fall frost
Oct 26
Growing season
190 days
Hardiness zone
7a
In an average year around Clifton, CO, the last spring frost (32°F) is about Apr 17 and the first fall frost is about Oct 26, giving roughly a 190-day growing season. To be safe most years, wait until Mar 27 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) | May 15 | Apr 30 | Apr 16 |
| Freeze (32°F) | May 3 | Apr 17 | Mar 27 |
| Hard (28°F) | Apr 20 | Apr 1 | Mar 7 |
| Severe (24°F) | Apr 7 | Mar 9 | Feb 22 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 15 | May 9 | May 5 | May 2 | Apr 30 | Apr 27 | Apr 24 | Apr 20 | Apr 16 |
| 32°F | May 3 | Apr 29 | Apr 24 | Apr 21 | Apr 17 | Apr 14 | Apr 10 | Apr 4 | Mar 27 |
| 28°F | Apr 20 | Apr 14 | Apr 9 | Apr 5 | Apr 1 | Mar 26 | Mar 20 | Mar 14 | Mar 7 |
| 24°F | Apr 7 | Mar 29 | Mar 20 | Mar 14 | Mar 9 | Mar 6 | Mar 3 | Feb 28 | Feb 22 |
| 20°F | Mar 12 | Mar 6 | Mar 2 | Feb 28 | Feb 23 | Feb 20 | Feb 16 | Feb 11 | Feb 3 |
| 16°F | Feb 28 | Feb 23 | Feb 18 | Feb 13 | Feb 9 | Feb 4 | Feb 1 | Jan 25 | Jan 14 |
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) | Oct 3 | Oct 16 | Oct 28 |
| Freeze (32°F) | Oct 12 | Oct 26 | Nov 10 |
| Hard (28°F) | Oct 20 | Nov 5 | Nov 20 |
| Severe (24°F) | Oct 31 | Nov 16 | Dec 1 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Oct 3 | Oct 7 | Oct 10 | Oct 13 | Oct 16 | Oct 19 | Oct 22 | Oct 25 | Oct 28 |
| 32°F | Oct 12 | Oct 16 | Oct 19 | Oct 22 | Oct 26 | Oct 29 | Nov 1 | Nov 4 | Nov 10 |
| 28°F | Oct 20 | Oct 26 | Oct 30 | Nov 2 | Nov 5 | Nov 9 | Nov 12 | Nov 16 | Nov 20 |
| 24°F | Oct 31 | Nov 5 | Nov 10 | Nov 14 | Nov 16 | Nov 19 | Nov 22 | Nov 26 | Dec 1 |
| 20°F | Nov 10 | Nov 17 | Nov 21 | Nov 24 | Nov 27 | Dec 1 | Dec 4 | Dec 8 | Dec 14 |
| 16°F | Nov 20 | Nov 27 | Dec 1 | Dec 5 | Dec 8 | Dec 12 | Dec 15 | Dec 20 | Dec 25 |
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: Palisade, Co, about 4.5 miles away@if(!empty($station['elevation_ft'])), at 4,751 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 Clifton, CO?
On average, the last spring frost (32°F) around Clifton, CO is about Apr 17. In cooler years it can run later, so for a safer bet many gardeners wait until Mar 27.
When is the first frost in the fall?
The first fall frost around Clifton, CO typically arrives about Oct 26. 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 Apr 17 on average, or Mar 27 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 190 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 81520 Planting calendar → Colorado frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026