Last spring frost
May 2
Frost Dates for Evans, CO
First fall frost
Oct 8
Growing season
159 days
Hardiness zone
5b
In an average year around Evans, CO, the last spring frost (32°F) is about May 2 and the first fall frost is about Oct 8, giving roughly a 159-day growing season. To be safe most years, wait until Apr 17 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 26 | May 12 | May 1 |
| Freeze (32°F) | May 14 | May 2 | Apr 17 |
| Hard (28°F) | May 5 | Apr 20 | Apr 5 |
| Severe (24°F) | Apr 24 | Apr 6 | Mar 19 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 26 | May 20 | May 17 | May 15 | May 12 | May 10 | May 8 | May 4 | May 1 |
| 32°F | May 14 | May 10 | May 7 | May 5 | May 2 | Apr 30 | Apr 27 | Apr 22 | Apr 17 |
| 28°F | May 5 | May 1 | Apr 27 | Apr 24 | Apr 20 | Apr 17 | Apr 14 | Apr 10 | Apr 5 |
| 24°F | Apr 24 | Apr 19 | Apr 14 | Apr 10 | Apr 6 | Apr 3 | Mar 31 | Mar 26 | Mar 19 |
| 20°F | Apr 14 | Apr 7 | Apr 2 | Mar 30 | Mar 26 | Mar 22 | Mar 17 | Mar 13 | Mar 7 |
| 16°F | Apr 3 | Mar 28 | Mar 21 | Mar 16 | Mar 11 | Mar 7 | Mar 4 | Feb 28 | Feb 23 |
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 18 | Sep 30 | Oct 11 |
| Freeze (32°F) | Sep 26 | Oct 8 | Oct 21 |
| Hard (28°F) | Oct 4 | Oct 18 | Nov 1 |
| Severe (24°F) | Oct 13 | Oct 28 | Nov 10 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 18 | Sep 23 | Sep 25 | Sep 28 | Sep 30 | Oct 2 | Oct 4 | Oct 7 | Oct 11 |
| 32°F | Sep 26 | Oct 1 | Oct 3 | Oct 5 | Oct 8 | Oct 11 | Oct 14 | Oct 17 | Oct 21 |
| 28°F | Oct 4 | Oct 9 | Oct 12 | Oct 15 | Oct 18 | Oct 21 | Oct 24 | Oct 27 | Nov 1 |
| 24°F | Oct 13 | Oct 18 | Oct 22 | Oct 25 | Oct 28 | Nov 1 | Nov 3 | Nov 7 | Nov 10 |
| 20°F | Oct 20 | Oct 26 | Oct 31 | Nov 3 | Nov 6 | Nov 9 | Nov 12 | Nov 15 | Nov 19 |
| 16°F | Oct 27 | Nov 3 | Nov 7 | Nov 11 | Nov 14 | Nov 17 | Nov 20 | Nov 24 | Nov 28 |
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: Greeley Unc, Co, about 2 miles away@if(!empty($station['elevation_ft'])), at 4,715 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 Evans, CO?
On average, the last spring frost (32°F) around Evans, CO is about May 2. In cooler years it can run later, so for a safer bet many gardeners wait until Apr 17.
When is the first frost in the fall?
The first fall frost around Evans, CO typically arrives about Oct 8. 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 May 2 on average, or Apr 17 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 159 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 80620 Planting calendar → Colorado frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026