Last spring frost
May 21
Frost Dates for Redlands, CO
First fall frost
Sep 26
Growing season
126 days
Hardiness zone
6b
In an average year around Redlands, CO, the last spring frost (32°F) is about May 21 and the first fall frost is about Sep 26, giving roughly a 126-day growing season. To be safe most years, wait until May 6 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 19 | Jun 2 | May 19 |
| Freeze (32°F) | Jun 9 | May 21 | May 6 |
| Hard (28°F) | May 27 | May 6 | Apr 21 |
| Severe (24°F) | May 10 | Apr 23 | Apr 6 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Jun 19 | Jun 13 | Jun 9 | Jun 5 | Jun 2 | May 31 | May 28 | May 24 | May 19 |
| 32°F | Jun 9 | Jun 3 | May 29 | May 24 | May 21 | May 18 | May 16 | May 12 | May 6 |
| 28°F | May 27 | May 18 | May 13 | May 10 | May 6 | May 3 | May 1 | Apr 27 | Apr 21 |
| 24°F | May 10 | May 3 | Apr 29 | Apr 26 | Apr 23 | Apr 19 | Apr 16 | Apr 12 | Apr 6 |
| 20°F | Apr 24 | Apr 19 | Apr 16 | Apr 12 | Apr 8 | Apr 5 | Apr 2 | Mar 28 | Mar 19 |
| 16°F | Apr 9 | Apr 4 | Apr 1 | Mar 28 | Mar 22 | Mar 17 | Mar 13 | Mar 8 | Mar 4 |
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 5 | Sep 19 | Sep 29 |
| Freeze (32°F) | Sep 14 | Sep 26 | Oct 8 |
| Hard (28°F) | Sep 23 | Oct 5 | Oct 19 |
| Severe (24°F) | Oct 1 | Oct 14 | Oct 31 |
Show full probability table (all thresholds & percentiles)
| °F | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 5 | Sep 9 | Sep 13 | Sep 16 | Sep 19 | Sep 22 | Sep 24 | Sep 26 | Sep 29 |
| 32°F | Sep 14 | Sep 17 | Sep 21 | Sep 24 | Sep 26 | Sep 29 | Oct 1 | Oct 4 | Oct 8 |
| 28°F | Sep 23 | Sep 27 | Sep 30 | Oct 3 | Oct 5 | Oct 8 | Oct 10 | Oct 14 | Oct 19 |
| 24°F | Oct 1 | Oct 5 | Oct 8 | Oct 11 | Oct 14 | Oct 18 | Oct 20 | Oct 24 | Oct 31 |
| 20°F | Oct 9 | Oct 14 | Oct 18 | Oct 22 | Oct 24 | Oct 28 | Nov 1 | Nov 4 | Nov 9 |
| 16°F | Oct 18 | Oct 24 | Oct 29 | Nov 2 | Nov 5 | Nov 9 | Nov 13 | Nov 17 | Nov 22 |
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: Glade Park 17W, Co, about 9 miles away@if(!empty($station['elevation_ft'])), at 6,323 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 Redlands, CO?
On average, the last spring frost (32°F) around Redlands, CO is about May 21. In cooler years it can run later, so for a safer bet many gardeners wait until May 6.
When is the first frost in the fall?
The first fall frost around Redlands, CO typically arrives about Sep 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 May 21 on average, or May 6 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 126 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 81523 Planting calendar → Colorado frost dates →
Data source: NOAA 1991–2020 Climate Normals · Page updated Aug 4, 2026