When to plant in Helena Valley Northeast, MT
Planting dates worked out from Helena Valley Northeast's own frost records, not a generic zone chart.
Safe to plant out
May 23
1 year in 10 has a later frost
Average last frost
May 11
about a 50% chance of a later one
Average first fall frost
Sep 27
1 year in 10 by Sep 11
Frost-free days
139
median, 1991–2020
Station used: Helena Montana · 4.4 km away · station 1170 m, town 1114 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 | Mar 28 – Apr 11 | May 23 – Jun 6 | Jul 17 |
| Sweet pepper | Mar 14 – Mar 28 | May 23 – Jun 6 | Jul 22 |
| Lettuce (leaf) | Mar 9 – Mar 16 | Apr 13 – Apr 27 | May 23 |
| Peas | — | Apr 10 – May 8 | Jun 4 |
| Bush beans | — | May 16 – Jun 6 | Jul 5 |
| Carrot | — | Apr 24 – Jun 5 | Jun 23 |
| Beet | — | Apr 24 – Jun 5 | Jun 13 |
| Potato | — | Apr 24 – May 15 | Jul 3 |
| Kale | Mar 6 – Mar 20 | Apr 17 – May 1 | May 30 |
| Broccoli | Mar 2 – Mar 16 | Apr 13 – May 4 | Jun 12 |
| Cucumber | Apr 25 – May 2 | May 23 – Jun 6 | Jul 12 |
| Summer squash and zucchini | Apr 25 – May 2 | May 23 – Jun 6 | Jul 7 |
| Winter squash | Apr 25 – May 2 | May 23 – Jun 6 | Aug 11 |
| Sweet corn | — | May 16 – Jun 6 | Jul 15 |
| Onion (from sets) | — | Apr 13 – May 4 | Jul 12 |
| Garlic | — | Sep 13 – Oct 11 (fall) | following summer |
| Spinach | — | Apr 10 – May 8 | May 18 |
| Basil | Apr 11 – Apr 25 | May 23 – Jun 6 | Jul 19 |
Helena Valley Northeast'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 |
|---|---|
| 2001 | May 21 |
| 2002 | May 23 |
| 2003 | May 20 |
| 2004 | May 25 |
| 2005 | May 3 |
| 2006 | May 5 |
| 2007 | Apr 22 |
| 2008 | May 10 |
| 2009 | May 16 |
| 2010 | May 13 |
| 2011 | May 2 |
| 2012 | May 27 |
| 2013 | May 2 |
| 2014 | May 14 |
| 2015 | May 11 |
| 2016 | May 11 |
| 2017 | May 16 |
| 2018 | Apr 26 |
| 2019 | May 10 |
| 2020 | May 5 |
| 2021 | May 23 |
| 2022 | May 23 |
| 2023 | May 10 |
| 2024 | May 31 |
Each year's frost-free daysLong-term trend
See the data as a table
| Year | Frost-free days |
|---|---|
| 2002 | 121 |
| 2003 | 119 |
| 2004 | 138 |
| 2005 | 130 |
| 2006 | 156 |
| 2007 | 160 |
| 2008 | 150 |
| 2009 | 138 |
| 2010 | 151 |
| 2011 | 140 |
| 2012 | 129 |
| 2013 | 146 |
| 2014 | 119 |
| 2015 | 139 |
| 2016 | 151 |
| 2017 | 130 |
| 2018 | 157 |
| 2019 | 140 |
| 2020 | 125 |
| 2021 | 116 |
| 2022 | 109 |
| 2023 | 166 |
| 2024 | 124 |
Each year's average temperature, April to SeptemberLong-term trend
See the data as a table
| Year | Growing-season temperature |
|---|---|
| 2001 | 16.1 °C |
| 2002 | 14.5 °C |
| 2003 | 16.5 °C |
| 2004 | 14.9 °C |
| 2005 | 15.0 °C |
| 2006 | 16.7 °C |
| 2007 | 15.6 °C |
| 2008 | 14.8 °C |
| 2009 | 15.2 °C |
| 2010 | 14.4 °C |
| 2011 | 14.9 °C |
| 2012 | 16.1 °C |
| 2013 | 15.8 °C |
| 2014 | 15.0 °C |
| 2015 | 15.5 °C |
| 2016 | 15.2 °C |
| 2017 | 15.8 °C |
| 2018 | 14.7 °C |
| 2019 | 14.7 °C |
| 2020 | 14.8 °C |
| 2021 | 15.7 °C |
| 2022 | 15.0 °C |
| 2023 | 15.6 °C |
| 2024 | 15.4 °C |
What this means for you: This station's record is too short to show a reliable trend yet.
Source: daily records from Helena Montana (NOAA GHCN-Daily). Years with too many missing days are left out.