When to plant in Big Sky, MT
Planting dates worked out from Big Sky's own frost records, not a generic zone chart.
Safe to plant out
Jul 5
1 year in 10 has a later frost
Average last frost
Jun 22
about a 50% chance of a later one
Average first fall frost
Aug 31
1 year in 10 by Aug 3
Frost-free days
74
median, 1991–2020
Station used: Lick Creek · 39.3 km away · station 2091 m, town 2200 m. How we match towns to stations
This season
Plan your garden.
Planting dates for common crops
| Crop | Start indoors | Plant out or sow | Harvest from |
|---|---|---|---|
| Tomato Season likely too short |
May 10 – May 24 | Jul 5 – Jul 19 | Aug 29 |
| Sweet pepper Season likely too short |
Apr 26 – May 10 | Jul 5 – Jul 19 | Sep 3 |
| Lettuce (leaf) | Apr 20 – Apr 27 | May 25 – Jun 8 | Jul 4 |
| Peas | — | May 14 – Jun 11 | Jul 8 |
| Bush beans Season likely too short |
— | Jun 28 – Jul 19 | Aug 17 |
| Carrot | — | Jun 1 – Jul 13 | Jul 31 |
| Beet | — | May 26 – Jul 7 | Jul 15 |
| Potato | — | Jun 1 – Jun 22 | Aug 10 |
| Kale | Apr 13 – Apr 27 | May 25 – Jun 8 | Jul 7 |
| Broccoli | Apr 13 – Apr 27 | May 25 – Jun 15 | Jul 24 |
| Cucumber Season likely too short |
Jun 7 – Jun 14 | Jul 5 – Jul 19 | Aug 24 |
| Summer squash and zucchini Season likely too short |
Jun 7 – Jun 14 | Jul 5 – Jul 19 | Aug 19 |
| Winter squash Season likely too short |
Jun 7 – Jun 14 | Jul 5 – Jul 19 | Sep 23 |
| Sweet corn Season likely too short |
— | Jun 28 – Jul 19 | Aug 27 |
| Onion (from sets) | — | May 25 – Jun 15 | Aug 23 |
| Garlic | — | Aug 17 – Sep 14 (fall) | following summer |
| Spinach | — | May 14 – Jun 11 | Jun 21 |
| Basil Season likely too short |
May 24 – Jun 7 | Jul 5 – Jul 19 | Aug 31 |
Big Sky's weather over time
How the growing season has shifted here, year by year, from the station's own records.
Each year's last spring frostLong-term trend
See the data as a table
| Year | Last spring frost |
|---|---|
| 1983 | Jul 11 |
| 1994 | Jul 11 |
| 1995 | Jun 30 |
| 1996 | Jul 6 |
| 1997 | Jul 2 |
| 1998 | Jun 21 |
| 1999 | Jun 28 |
| 2000 | Jun 26 |
| 2001 | Jun 16 |
| 2002 | Jun 20 |
| 2003 | Jun 25 |
| 2004 | Jun 17 |
| 2005 | Jul 4 |
| 2006 | Jun 18 |
| 2007 | Jun 26 |
| 2008 | Jul 12 |
| 2009 | Jun 23 |
| 2010 | Jun 18 |
| 2011 | Jun 4 |
| 2012 | Jun 19 |
| 2013 | Jun 15 |
| 2014 | May 30 |
| 2015 | May 18 |
| 2016 | Jun 25 |
| 2017 | Jun 23 |
| 2018 | Jul 4 |
| 2019 | Jun 9 |
| 2020 | Jun 15 |
| 2021 | Jun 11 |
| 2022 | Jun 26 |
| 2023 | Jun 22 |
| 2024 | Jun 19 |
Each year's frost-free daysLong-term trend
See the data as a table
| Year | Frost-free days |
|---|---|
| 1983 | 3 |
| 1994 | 41 |
| 1995 | 29 |
| 1996 | 28 |
| 1997 | 74 |
| 1998 | 91 |
| 1999 | 63 |
| 2000 | 71 |
| 2001 | 83 |
| 2002 | 41 |
| 2003 | 75 |
| 2004 | 71 |
| 2005 | 39 |
| 2006 | 73 |
| 2007 | 73 |
| 2008 | 51 |
| 2009 | 76 |
| 2010 | 80 |
| 2011 | 90 |
| 2012 | 66 |
| 2013 | 96 |
| 2014 | 97 |
| 2015 | 109 |
| 2016 | 60 |
| 2017 | 83 |
| 2018 | 77 |
| 2019 | 110 |
| 2020 | 83 |
| 2021 | 96 |
| 2022 | 74 |
| 2023 | 89 |
| 2024 | 93 |
Each year's average temperature, April to SeptemberLong-term trend
See the data as a table
| Year | Growing-season temperature |
|---|---|
| 1983 | 9.5 °C |
| 1993 | 7.8 °C |
| 1994 | 10.5 °C |
| 1995 | 8.4 °C |
| 1996 | 9.0 °C |
| 1997 | 8.9 °C |
| 1998 | 10.0 °C |
| 1999 | 8.9 °C |
| 2000 | 10.3 °C |
| 2001 | 10.9 °C |
| 2002 | 9.2 °C |
| 2003 | 10.2 °C |
| 2004 | 8.8 °C |
| 2005 | 9.2 °C |
| 2006 | 10.7 °C |
| 2007 | 11.1 °C |
| 2008 | 9.0 °C |
| 2009 | 10.1 °C |
| 2010 | 9.2 °C |
| 2011 | 9.8 °C |
| 2012 | 11.3 °C |
| 2013 | 10.8 °C |
| 2014 | 9.9 °C |
| 2015 | 10.6 °C |
| 2016 | 10.3 °C |
| 2017 | 10.2 °C |
| 2018 | 9.8 °C |
| 2019 | 9.3 °C |
| 2020 | 10.0 °C |
| 2021 | 10.8 °C |
| 2022 | 10.0 °C |
| 2023 | 10.4 °C |
| 2024 | 10.5 °C |
What this means for you: Since 1983, Big Sky's last spring frost has come about 6 days earlier per decade, on average. The frost-free season has grown by about 17 days per decade. Year-to-year swings are large, so keep using the safe date rather than the trend.
Source: daily records from Lick Creek (NOAA GHCN-Daily). Years with too many missing days are left out.