When to plant in Air Force Academy, CO
Planting dates worked out from Air Force Academy's own frost records, not a generic zone chart.
Last spring frost
- Early · riskyApr 239 years in 10 still get a later frost
- TypicalMay 7about half of years get a later frost
- Safe to plant outMay 201 year in 10 gets a later frost
Hardy crops like peas and spinach are timed from the typical date. Wait for the safe date before planting out tomatoes, peppers and squash.
First fall frost
- EarlySep 171 year in 10 has frost by then
- TypicalOct 5about half of years have had frost
- LateOct 219 years in 10 have had frost by then
A typical year has 149 frost-free days. Plan for tender crops to be ripe by the early date.
Station used: Ft. Carson Colorado · 37.3 km away · station 2042 m, town 2069 m. How we match towns to stations
Plan your garden.
Planting dates for common crops
| Crop | Start indoors | Plant out or sow | Harvest from |
|---|---|---|---|
| Tomato | Mar 25 – Apr 8 | May 20 – Jun 3 | Jul 14 |
| Sweet pepper | Mar 11 – Mar 25 | May 20 – Jun 3 | Jul 19 |
| Lettuce (leaf) | Mar 5 – Mar 12 | Apr 9 – Apr 23 | May 19 |
| Peas | — | Mar 26 – Apr 23 | May 20 |
| Bush beans | — | May 13 – Jun 3 | Jul 2 |
| Carrot | — | Apr 16 – May 28 | Jun 15 |
| Beet | — | Apr 12 – May 24 | Jun 1 |
| Potato | — | Apr 16 – May 7 | Jun 25 |
| Kale | Feb 26 – Mar 12 | Apr 9 – Apr 23 | May 22 |
| Broccoli | Feb 26 – Mar 12 | Apr 9 – Apr 30 | Jun 8 |
| Cucumber | Apr 22 – Apr 29 | May 20 – Jun 3 | Jul 9 |
| Summer squash and zucchini | Apr 22 – Apr 29 | May 20 – Jun 3 | Jul 4 |
| Winter squash | Apr 22 – Apr 29 | May 20 – Jun 3 | Aug 8 |
| Sweet corn | — | May 13 – Jun 3 | Jul 12 |
| Onion (from sets) | — | Apr 9 – Apr 30 | Jul 8 |
| Garlic | — | Sep 21 – Oct 19 (fall) | following summer |
| Spinach | — | Mar 26 – Apr 23 | May 3 |
| Basil | Apr 8 – Apr 22 | May 20 – Jun 3 | Jul 16 |
Air Force Academy's weather over time
How the growing season has shifted here, year by year, from the station's own records.
See the data as a table
| Year | Last spring frost |
|---|---|
| 1994 | Apr 30 |
| 1995 | May 2 |
| 1996 | Apr 29 |
| 1997 | May 2 |
| 1998 | Apr 20 |
| 1999 | May 12 |
| 2000 | May 12 |
| 2001 | May 21 |
| 2002 | May 9 |
| 2003 | May 11 |
| 2004 | May 1 |
| 2005 | May 12 |
| 2006 | May 10 |
| 2007 | May 24 |
| 2008 | May 11 |
| 2009 | Apr 27 |
| 2010 | May 13 |
| 2011 | May 15 |
| 2012 | Apr 15 |
| 2013 | May 4 |
| 2014 | May 13 |
| 2015 | May 11 |
| 2016 | May 2 |
| 2017 | May 20 |
| 2018 | Apr 25 |
| 2019 | May 21 |
| 2020 | Apr 18 |
| 2021 | May 11 |
| 2022 | May 22 |
| 2023 | Apr 23 |
| 2024 | Apr 21 |
| 2025 | Apr 20 |
See the data as a table
| Year | Frost-free days |
|---|---|
| 1994 | 143 |
| 1995 | 140 |
| 1996 | 149 |
| 1997 | 163 |
| 1998 | 167 |
| 1999 | 138 |
| 2000 | 133 |
| 2001 | 136 |
| 2002 | 160 |
| 2003 | 125 |
| 2004 | 164 |
| 2005 | 146 |
| 2006 | 152 |
| 2007 | 149 |
| 2008 | 162 |
| 2010 | 165 |
| 2011 | 145 |
| 2012 | 171 |
| 2013 | 152 |
| 2014 | 121 |
| 2015 | 169 |
| 2016 | 157 |
| 2017 | 141 |
| 2018 | 167 |
| 2019 | 141 |
| 2020 | 142 |
| 2021 | 156 |
| 2022 | 153 |
| 2023 | 172 |
| 2024 | 177 |
| 2025 | 181 |
See the data as a table
| Year | Growing-season temperature |
|---|---|
| 1994 | 17.2 °C |
| 1995 | 14.9 °C |
| 1996 | 16.7 °C |
| 1997 | 16.6 °C |
| 1998 | 17.7 °C |
| 1999 | 15.6 °C |
| 2000 | 17.9 °C |
| 2001 | 17.9 °C |
| 2002 | 18.4 °C |
| 2003 | 17.2 °C |
| 2004 | 16.0 °C |
| 2005 | 17.3 °C |
| 2006 | 17.3 °C |
| 2007 | 17.0 °C |
| 2008 | 16.7 °C |
| 2009 | 16.1 °C |
| 2010 | 17.5 °C |
| 2011 | 17.4 °C |
| 2012 | 18.7 °C |
| 2013 | 17.3 °C |
| 2014 | 17.0 °C |
| 2015 | 17.3 °C |
| 2016 | 17.3 °C |
| 2017 | 16.8 °C |
| 2018 | 18.9 °C |
| 2019 | 17.6 °C |
| 2020 | 18.4 °C |
| 2021 | 17.7 °C |
| 2022 | 18.1 °C |
| 2023 | 17.4 °C |
| 2024 | 18.5 °C |
| 2025 | 17.5 °C |
What this means for you: Since 1994, Air Force Academy's last spring frost has come about 1 day earlier per decade, on average. The frost-free season has grown by about 6 days per decade. Year-to-year swings are large, so keep using the safe date rather than the trend.
Source: daily records from Ft. Carson Colorado (NOAA GHCN-Daily). Years with too many missing days are left out.