When to plant in Hardin, MT
Planting dates worked out from Hardin's own frost records, not a generic zone chart.
Safe to plant out
May 26
1 year in 10 has a later frost
Average last frost
May 12
about a 50% chance of a later one
Average first fall frost
Sep 30
1 year in 10 by Sep 13
Frost-free days
143
median, 1991–2020
Station used: Hardin · 0.2 km away · station 878 m, town 886 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 31 – Apr 14 | May 26 – Jun 9 | Jul 20 |
| Sweet pepper | Mar 17 – Mar 31 | May 26 – Jun 9 | Jul 25 |
| Lettuce (leaf) | Mar 10 – Mar 17 | Apr 14 – Apr 28 | May 24 |
| Peas | — | Mar 31 – Apr 28 | May 25 |
| Bush beans | — | May 19 – Jun 9 | Jul 8 |
| Carrot | — | Apr 21 – Jun 2 | Jun 20 |
| Beet | — | Apr 14 – May 26 | Jun 3 |
| Potato | — | Apr 21 – May 12 | Jun 30 |
| Kale | Mar 3 – Mar 17 | Apr 14 – Apr 28 | May 27 |
| Broccoli | Mar 3 – Mar 17 | Apr 14 – May 5 | Jun 13 |
| Cucumber | Apr 28 – May 5 | May 26 – Jun 9 | Jul 15 |
| Summer squash and zucchini | Apr 28 – May 5 | May 26 – Jun 9 | Jul 10 |
| Winter squash | Apr 28 – May 5 | May 26 – Jun 9 | Aug 14 |
| Sweet corn | — | May 19 – Jun 9 | Jul 18 |
| Onion (from sets) | — | Apr 14 – May 5 | Jul 13 |
| Garlic | — | Sep 16 – Oct 14 (fall) | following summer |
| Spinach | — | Mar 31 – Apr 28 | May 8 |
| Basil | Apr 14 – Apr 28 | May 26 – Jun 9 | Jul 22 |
Hardin'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 |
|---|---|
| 1949 | May 24 |
| 1950 | Jun 8 |
| 1951 | Jun 3 |
| 1952 | May 18 |
| 1953 | Jun 25 |
| 1954 | May 31 |
| 1955 | May 7 |
| 1956 | May 4 |
| 1957 | Apr 27 |
| 1958 | May 1 |
| 1959 | May 13 |
| 1960 | May 6 |
| 1961 | May 8 |
| 1962 | May 1 |
| 1963 | May 22 |
| 1964 | Jun 2 |
| 1965 | Jun 8 |
| 1966 | May 19 |
| 1967 | May 15 |
| 1968 | May 21 |
| 1969 | Jun 14 |
| 1970 | May 13 |
| 1971 | May 18 |
| 1974 | May 17 |
| 1977 | May 5 |
| 1978 | Apr 24 |
| 1982 | May 31 |
| 1986 | May 17 |
| 1987 | Apr 21 |
| 1988 | Apr 27 |
| 1989 | May 1 |
| 1990 | May 14 |
| 1991 | May 27 |
| 1993 | Apr 25 |
| 1994 | Apr 30 |
| 1995 | May 14 |
| 1996 | May 10 |
| 1997 | May 19 |
| 1999 | May 8 |
| 2000 | May 13 |
| 2001 | May 7 |
| 2002 | May 24 |
| 2003 | May 21 |
| 2004 | May 27 |
| 2005 | May 13 |
| 2006 | May 11 |
| 2007 | Apr 14 |
| 2009 | Jun 8 |
| 2010 | May 9 |
| 2011 | May 5 |
| 2012 | May 12 |
| 2013 | May 5 |
| 2015 | May 11 |
| 2016 | May 15 |
| 2017 | May 23 |
| 2018 | Apr 25 |
| 2019 | May 10 |
| 2020 | May 9 |
| 2021 | May 14 |
| 2022 | May 25 |
| 2023 | Apr 29 |
| 2024 | Jun 16 |
| 2025 | May 2 |
| 2026 | May 19 |
Each year's frost-free daysLong-term trend
See the data as a table
| Year | Frost-free days |
|---|---|
| 1949 | 111 |
| 1950 | 98 |
| 1952 | 106 |
| 1953 | 87 |
| 1954 | 112 |
| 1955 | 137 |
| 1956 | 141 |
| 1957 | 144 |
| 1958 | 141 |
| 1959 | 138 |
| 1960 | 139 |
| 1961 | 117 |
| 1962 | 125 |
| 1963 | 148 |
| 1964 | 101 |
| 1965 | 99 |
| 1966 | 143 |
| 1967 | 154 |
| 1968 | 123 |
| 1969 | 112 |
| 1970 | 122 |
| 1974 | 118 |
| 1977 | 141 |
| 1986 | 127 |
| 1987 | 149 |
| 1988 | 144 |
| 1989 | 131 |
| 1990 | 108 |
| 1991 | 113 |
| 1993 | 141 |
| 1994 | 160 |
| 1995 | 129 |
| 1996 | 139 |
| 1997 | 142 |
| 1999 | 147 |
| 2000 | 131 |
| 2001 | 150 |
| 2002 | 120 |
| 2003 | 119 |
| 2004 | 133 |
| 2005 | 144 |
| 2006 | 152 |
| 2007 | 184 |
| 2010 | 155 |
| 2012 | 146 |
| 2013 | 151 |
| 2015 | 156 |
| 2016 | 143 |
| 2017 | 133 |
| 2018 | 153 |
| 2019 | 143 |
| 2020 | 122 |
| 2021 | 125 |
| 2022 | 140 |
| 2023 | 159 |
| 2024 | 106 |
| 2025 | 157 |
Each year's average temperature, April to SeptemberLong-term trend
See the data as a table
| Year | Growing-season temperature |
|---|---|
| 1949 | 17.6 °C |
| 1950 | 14.7 °C |
| 1951 | 14.9 °C |
| 1952 | 16.7 °C |
| 1953 | 15.3 °C |
| 1954 | 16.8 °C |
| 1955 | 16.9 °C |
| 1956 | 16.1 °C |
| 1957 | 15.9 °C |
| 1958 | 16.2 °C |
| 1959 | 15.9 °C |
| 1960 | 16.6 °C |
| 1961 | 16.5 °C |
| 1962 | 15.9 °C |
| 1963 | 16.9 °C |
| 1964 | 15.5 °C |
| 1965 | 14.3 °C |
| 1966 | 16.7 °C |
| 1967 | 15.3 °C |
| 1968 | 14.5 °C |
| 1969 | 15.9 °C |
| 1970 | 15.2 °C |
| 1974 | 16.6 °C |
| 1977 | 16.1 °C |
| 1993 | 15.7 °C |
| 1994 | 18.1 °C |
| 1995 | 16.1 °C |
| 1996 | 17.1 °C |
| 1999 | 17.2 °C |
| 2000 | 18.5 °C |
| 2001 | 19.1 °C |
| 2002 | 17.8 °C |
| 2003 | 18.9 °C |
| 2004 | 17.3 °C |
| 2005 | 17.8 °C |
| 2006 | 18.9 °C |
| 2007 | 19.0 °C |
| 2010 | 17.2 °C |
| 2011 | 17.4 °C |
| 2012 | 18.2 °C |
| 2013 | 17.4 °C |
| 2015 | 17.7 °C |
| 2016 | 17.3 °C |
| 2017 | 17.7 °C |
| 2018 | 17.1 °C |
| 2019 | 16.5 °C |
| 2020 | 16.9 °C |
| 2021 | 17.9 °C |
| 2022 | 17.3 °C |
| 2023 | 17.8 °C |
| 2024 | 17.5 °C |
| 2025 | 17.6 °C |
| 2026 | 17.8 °C |
What this means for you: Since 1949, Hardin's last spring frost has come about 1 day earlier per decade, on average. The frost-free season has grown by about 3 days per decade. Year-to-year swings are large, so keep using the safe date rather than the trend.
Source: daily records from Hardin (NOAA GHCN-Daily). Years with too many missing days are left out.