When to plant in Glendale, CO
Planting dates worked out from Glendale's own frost records, not a generic zone chart.
Safe to plant out
May 21
1 year in 10 has a later frost
Average last frost
May 7
about a 50% chance of a later one
Average first fall frost
Oct 6
1 year in 10 by Sep 19
Frost-free days
150
median, 1991–2020
Station used: Denver-Stapleton · 8.5 km away · station 1611 m, town 1631 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 26 – Apr 9 | May 21 – Jun 4 | Jul 15 |
| Sweet pepper | Mar 12 – Mar 26 | May 21 – Jun 4 | Jul 20 |
| Lettuce (leaf) | Mar 5 – Mar 12 | Apr 9 – Apr 23 | May 19 |
| Peas | — | Mar 26 – Apr 23 | May 20 |
| Bush beans | — | May 14 – Jun 4 | Jul 3 |
| Carrot | — | Apr 16 – May 28 | Jun 15 |
| Beet | — | Apr 9 – May 21 | May 29 |
| 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 23 – Apr 30 | May 21 – Jun 4 | Jul 10 |
| Summer squash and zucchini | Apr 23 – Apr 30 | May 21 – Jun 4 | Jul 5 |
| Winter squash | Apr 23 – Apr 30 | May 21 – Jun 4 | Aug 9 |
| Sweet corn | — | May 14 – Jun 4 | Jul 13 |
| Onion (from sets) | — | Apr 9 – Apr 30 | Jul 8 |
| Garlic | — | Sep 22 – Oct 20 (fall) | following summer |
| Spinach | — | Mar 26 – Apr 23 | May 3 |
| Basil | Apr 9 – Apr 23 | May 21 – Jun 4 | Jul 17 |
Glendale'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 |
|---|---|
| 1948 | May 10 |
| 1949 | Apr 15 |
| 1950 | May 26 |
| 1951 | Jun 2 |
| 1952 | Apr 23 |
| 1953 | May 13 |
| 1954 | May 3 |
| 1955 | Apr 28 |
| 1956 | Apr 24 |
| 1957 | May 17 |
| 1958 | Apr 30 |
| 1959 | Apr 22 |
| 1960 | May 1 |
| 1961 | May 13 |
| 1962 | Apr 13 |
| 1963 | Apr 24 |
| 1964 | May 12 |
| 1965 | May 9 |
| 1966 | May 13 |
| 1967 | May 14 |
| 1968 | May 19 |
| 1969 | Apr 28 |
| 1970 | May 15 |
| 1971 | May 19 |
| 1972 | May 3 |
| 1973 | May 2 |
| 1974 | Apr 16 |
| 1975 | May 1 |
| 1976 | Apr 18 |
| 1977 | Apr 5 |
| 1978 | May 7 |
| 1979 | May 11 |
| 1980 | Apr 14 |
| 1981 | Apr 5 |
| 1982 | May 6 |
| 1983 | May 18 |
| 1984 | Apr 30 |
| 1985 | Apr 27 |
| 1986 | Apr 19 |
| 1987 | Apr 21 |
| 1988 | May 3 |
| 1989 | May 1 |
| 1990 | May 10 |
| 1991 | May 1 |
| 1992 | Apr 25 |
| 1993 | May 2 |
| 1994 | Apr 30 |
| 1995 | May 1 |
| 1996 | Apr 29 |
| 1997 | May 3 |
| 1998 | Apr 29 |
| 1999 | May 6 |
| 2000 | May 13 |
| 2001 | May 21 |
| 2002 | May 24 |
| 2003 | May 12 |
| 2004 | May 13 |
| 2005 | May 12 |
| 2006 | May 11 |
| 2007 | Apr 15 |
| 2008 | May 14 |
| 2010 | May 14 |
| 2011 | May 6 |
| 2012 | Apr 28 |
| 2013 | May 4 |
| 2014 | May 15 |
| 2015 | May 11 |
| 2016 | May 3 |
| 2017 | May 21 |
| 2018 | Apr 26 |
| 2019 | May 22 |
| 2020 | Apr 19 |
| 2021 | May 12 |
| 2022 | May 22 |
| 2023 | Apr 24 |
| 2024 | Apr 28 |
Each year's frost-free daysLong-term trend
See the data as a table
| Year | Frost-free days |
|---|---|
| 1948 | 148 |
| 1949 | 178 |
| 1950 | 130 |
| 1951 | 110 |
| 1952 | 164 |
| 1953 | 143 |
| 1954 | 163 |
| 1955 | 177 |
| 1956 | 178 |
| 1957 | 159 |
| 1958 | 174 |
| 1959 | 159 |
| 1960 | 170 |
| 1961 | 134 |
| 1962 | 147 |
| 1963 | 185 |
| 1964 | 144 |
| 1965 | 129 |
| 1966 | 153 |
| 1967 | 154 |
| 1968 | 142 |
| 1969 | 158 |
| 1970 | 144 |
| 1971 | 120 |
| 1972 | 172 |
| 1973 | 161 |
| 1974 | 196 |
| 1975 | 141 |
| 1976 | 171 |
| 1977 | 179 |
| 1978 | 136 |
| 1979 | 163 |
| 1980 | 185 |
| 1981 | 199 |
| 1982 | 153 |
| 1983 | 124 |
| 1984 | 147 |
| 1985 | 148 |
| 1986 | 160 |
| 1987 | 170 |
| 1988 | 172 |
| 1989 | 167 |
| 1990 | 149 |
| 1991 | 156 |
| 1992 | 164 |
| 1993 | 134 |
| 1994 | 144 |
| 1995 | 141 |
| 1996 | 148 |
| 1997 | 162 |
| 1998 | 170 |
| 1999 | 144 |
| 2000 | 133 |
| 2001 | 136 |
| 2002 | 140 |
| 2003 | 154 |
| 2004 | 153 |
| 2005 | 147 |
| 2006 | 159 |
| 2007 | 183 |
| 2008 | 150 |
| 2010 | 147 |
| 2011 | 164 |
| 2012 | 159 |
| 2013 | 153 |
| 2014 | 121 |
| 2015 | 169 |
| 2016 | 169 |
| 2017 | 140 |
| 2018 | 166 |
| 2019 | 140 |
| 2020 | 142 |
| 2021 | 155 |
| 2023 | 171 |
| 2024 | 185 |
Each year's average temperature, April to SeptemberLong-term trend
See the data as a table
| Year | Growing-season temperature |
|---|---|
| 1948 | 18.3 °C |
| 1949 | 17.3 °C |
| 1950 | 16.1 °C |
| 1951 | 16.3 °C |
| 1952 | 18.2 °C |
| 1953 | 17.2 °C |
| 1954 | 18.8 °C |
| 1955 | 17.9 °C |
| 1956 | 18.1 °C |
| 1957 | 16.4 °C |
| 1958 | 17.7 °C |
| 1959 | 17.4 °C |
| 1960 | 18.1 °C |
| 1961 | 16.3 °C |
| 1962 | 17.8 °C |
| 1963 | 18.1 °C |
| 1964 | 17.4 °C |
| 1965 | 16.6 °C |
| 1966 | 17.5 °C |
| 1967 | 15.7 °C |
| 1968 | 16.1 °C |
| 1969 | 18.0 °C |
| 1970 | 16.8 °C |
| 1971 | 16.7 °C |
| 1972 | 17.2 °C |
| 1973 | 16.6 °C |
| 1974 | 17.6 °C |
| 1975 | 16.1 °C |
| 1976 | 17.4 °C |
| 1977 | 18.8 °C |
| 1978 | 17.5 °C |
| 1979 | 17.4 °C |
| 1980 | 18.6 °C |
| 1981 | 19.2 °C |
| 1982 | 16.8 °C |
| 1983 | 16.3 °C |
| 1984 | 17.1 °C |
| 1985 | 17.7 °C |
| 1986 | 17.7 °C |
| 1987 | 18.2 °C |
| 1988 | 18.5 °C |
| 1989 | 17.9 °C |
| 1990 | 18.1 °C |
| 1991 | 17.9 °C |
| 1992 | 17.9 °C |
| 1993 | 17.2 °C |
| 1994 | 19.4 °C |
| 1995 | 16.0 °C |
| 1996 | 17.9 °C |
| 1997 | 17.2 °C |
| 1998 | 17.8 °C |
| 1999 | 16.6 °C |
| 2000 | 18.8 °C |
| 2001 | 18.4 °C |
| 2002 | 18.7 °C |
| 2003 | 17.8 °C |
| 2004 | 16.7 °C |
| 2005 | 17.5 °C |
| 2006 | 18.1 °C |
| 2007 | 17.9 °C |
| 2008 | 17.0 °C |
| 2010 | 17.7 °C |
| 2011 | 17.3 °C |
| 2012 | 19.6 °C |
| 2013 | 17.6 °C |
| 2014 | 17.5 °C |
| 2015 | 17.6 °C |
| 2016 | 18.2 °C |
| 2017 | 18.2 °C |
| 2018 | 18.9 °C |
| 2019 | 18.1 °C |
| 2020 | 18.6 °C |
| 2021 | 18.6 °C |
| 2022 | 18.6 °C |
| 2023 | 17.6 °C |
| 2024 | 18.7 °C |
What this means for you: Since 1948, Glendale's last spring frost has stayed at about the same time of year. Year-to-year swings are large, so keep using the safe date rather than the trend.
Source: daily records from Denver-Stapleton (NOAA GHCN-Daily). Years with too many missing days are left out.