When to plant in Eureka, MT
Planting dates worked out from Eureka's own frost records, not a generic zone chart.
Safe to plant out
May 28
1 year in 10 has a later frost
Average last frost
May 15
about a 50% chance of a later one
Average first fall frost
Sep 20
1 year in 10 by Sep 5
Frost-free days
130
median, 1991–2020
Station used: Eureka Rs · 2.1 km away · station 772 m, town 787 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 | Apr 2 – Apr 16 | May 28 – Jun 11 | Jul 22 |
| Sweet pepper | Mar 19 – Apr 2 | May 28 – Jun 11 | Jul 27 |
| Lettuce (leaf) | Mar 13 – Mar 20 | Apr 17 – May 1 | May 27 |
| Peas | — | Apr 5 – May 3 | May 30 |
| Bush beans | — | May 21 – Jun 11 | Jul 10 |
| Carrot | — | Apr 24 – Jun 5 | Jun 23 |
| Beet | — | Apr 17 – May 29 | Jun 6 |
| Potato | — | Apr 24 – May 15 | Jul 3 |
| Kale | Mar 6 – Mar 20 | Apr 17 – May 1 | May 30 |
| Broccoli | Mar 6 – Mar 20 | Apr 17 – May 8 | Jun 16 |
| Cucumber | Apr 30 – May 7 | May 28 – Jun 11 | Jul 17 |
| Summer squash and zucchini | Apr 30 – May 7 | May 28 – Jun 11 | Jul 12 |
| Winter squash | Apr 30 – May 7 | May 28 – Jun 11 | Aug 16 |
| Sweet corn | — | May 21 – Jun 11 | Jul 20 |
| Onion (from sets) | — | Apr 17 – May 8 | Jul 16 |
| Garlic | — | Sep 6 – Oct 4 (fall) | following summer |
| Spinach | — | Apr 5 – May 3 | May 13 |
| Basil | Apr 16 – Apr 30 | May 28 – Jun 11 | Jul 24 |
Eureka'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 |
|---|---|
| 1961 | May 12 |
| 1962 | Jul 3 |
| 1963 | May 19 |
| 1964 | May 26 |
| 1965 | Jun 7 |
| 1966 | May 23 |
| 1967 | May 26 |
| 1968 | Jun 15 |
| 1969 | Jun 13 |
| 1970 | May 18 |
| 1971 | May 22 |
| 1972 | May 4 |
| 1973 | Jun 11 |
| 1974 | May 3 |
| 1975 | Jun 30 |
| 1976 | Jun 5 |
| 1977 | May 27 |
| 1978 | May 23 |
| 1979 | May 30 |
| 1980 | Jun 7 |
| 1981 | May 13 |
| 1982 | Jun 8 |
| 1983 | May 13 |
| 1984 | May 11 |
| 1985 | May 13 |
| 1986 | May 23 |
| 1987 | May 22 |
| 1988 | May 21 |
| 1989 | May 29 |
| 1990 | May 11 |
| 1991 | May 27 |
| 1992 | May 22 |
| 1993 | May 3 |
| 1994 | Apr 28 |
| 1995 | May 22 |
| 1996 | May 11 |
| 1997 | May 22 |
| 1998 | May 16 |
| 1999 | Jun 8 |
| 2000 | Jun 1 |
| 2001 | May 21 |
| 2002 | May 22 |
| 2003 | May 20 |
| 2004 | Apr 30 |
| 2005 | May 25 |
| 2006 | May 14 |
| 2007 | May 7 |
| 2008 | May 15 |
| 2009 | Jun 7 |
| 2010 | May 24 |
| 2011 | May 18 |
| 2012 | May 12 |
| 2013 | May 5 |
| 2015 | May 9 |
| 2016 | Apr 17 |
| 2017 | May 8 |
| 2018 | Apr 24 |
| 2019 | May 1 |
| 2020 | May 11 |
| 2021 | May 5 |
| 2022 | May 22 |
| 2023 | Apr 28 |
| 2024 | May 4 |
Each year's frost-free daysLong-term trend
See the data as a table
| Year | Frost-free days |
|---|---|
| 1961 | 122 |
| 1962 | 14 |
| 1963 | 141 |
| 1964 | 102 |
| 1965 | 90 |
| 1966 | 129 |
| 1967 | 109 |
| 1968 | 97 |
| 1969 | 76 |
| 1970 | 114 |
| 1971 | 114 |
| 1972 | 119 |
| 1973 | 68 |
| 1974 | 121 |
| 1975 | 91 |
| 1976 | 120 |
| 1977 | 105 |
| 1979 | 116 |
| 1981 | 133 |
| 1982 | 98 |
| 1983 | 115 |
| 1984 | 124 |
| 1985 | 134 |
| 1986 | 106 |
| 1987 | 117 |
| 1988 | 113 |
| 1989 | 102 |
| 1990 | 147 |
| 1991 | 117 |
| 1992 | 94 |
| 1993 | 132 |
| 1994 | 137 |
| 1995 | 121 |
| 1996 | 134 |
| 1997 | 138 |
| 1998 | 127 |
| 1999 | 84 |
| 2000 | 112 |
| 2001 | 133 |
| 2002 | 121 |
| 2003 | 132 |
| 2004 | 153 |
| 2005 | 104 |
| 2006 | 145 |
| 2007 | 129 |
| 2008 | 146 |
| 2009 | 105 |
| 2010 | 100 |
| 2011 | 133 |
| 2012 | 122 |
| 2015 | 130 |
| 2016 | 148 |
| 2017 | 130 |
| 2018 | 165 |
| 2019 | 152 |
| 2020 | 119 |
| 2021 | 149 |
| 2022 | 121 |
| 2023 | 178 |
| 2024 | 151 |
Each year's average temperature, April to SeptemberLong-term trend
See the data as a table
| Year | Growing-season temperature |
|---|---|
| 1961 | 14.8 °C |
| 1962 | 14.2 °C |
| 1963 | 15.0 °C |
| 1964 | 13.6 °C |
| 1965 | 13.7 °C |
| 1966 | 14.7 °C |
| 1967 | 15.6 °C |
| 1968 | 14.0 °C |
| 1969 | 15.1 °C |
| 1970 | 14.5 °C |
| 1971 | 14.6 °C |
| 1972 | 13.7 °C |
| 1973 | 14.6 °C |
| 1974 | 14.5 °C |
| 1975 | 14.0 °C |
| 1976 | 14.6 °C |
| 1977 | 14.0 °C |
| 1978 | 14.4 °C |
| 1979 | 15.4 °C |
| 1981 | 13.8 °C |
| 1982 | 14.1 °C |
| 1983 | 13.8 °C |
| 1984 | 14.1 °C |
| 1985 | 15.1 °C |
| 1986 | 14.7 °C |
| 1987 | 16.3 °C |
| 1988 | 15.6 °C |
| 1989 | 15.1 °C |
| 1990 | 15.4 °C |
| 1991 | 15.0 °C |
| 1992 | 16.0 °C |
| 1993 | 14.6 °C |
| 1994 | 16.5 °C |
| 1995 | 15.5 °C |
| 1996 | 14.2 °C |
| 1997 | 14.7 °C |
| 1998 | 16.3 °C |
| 1999 | 14.7 °C |
| 2001 | 15.5 °C |
| 2002 | 14.3 °C |
| 2003 | 16.0 °C |
| 2004 | 16.0 °C |
| 2005 | 13.9 °C |
| 2006 | 15.9 °C |
| 2007 | 16.0 °C |
| 2009 | 15.7 °C |
| 2010 | 14.3 °C |
| 2011 | 15.4 °C |
| 2012 | 15.5 °C |
| 2015 | 17.0 °C |
| 2016 | 16.5 °C |
| 2017 | 16.7 °C |
| 2018 | 16.2 °C |
| 2019 | 16.3 °C |
| 2020 | 16.1 °C |
| 2021 | 17.5 °C |
| 2022 | 15.2 °C |
| 2023 | 17.4 °C |
| 2024 | 16.7 °C |
| 2025 | 17.3 °C |
What this means for you: Since 1961, Eureka's last spring frost has come about 4 days earlier per decade, on average. The frost-free season has grown by about 7 days per decade. Year-to-year swings are large, so keep using the safe date rather than the trend.
Source: daily records from Eureka Rs (NOAA GHCN-Daily). Years with too many missing days are left out.