When to plant in Hawarden, IA
Planting dates worked out from Hawarden's own frost records, not a generic zone chart.
Safe to plant out
May 17
1 year in 10 has a later frost
Average last frost
May 2
about a 50% chance of a later one
Average first fall frost
Oct 2
1 year in 10 by Sep 17
Frost-free days
154
median, 1991–2020
Station used: Hawarden · 0.8 km away · station 363 m, town 360 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 22 – Apr 5 | May 17 – May 31 | Jul 11 |
| Sweet pepper | Mar 8 – Mar 22 | May 17 – May 31 | Jul 16 |
| Lettuce (leaf) | Mar 1 – Mar 8 | Apr 5 – Apr 19 | May 15 |
| Peas | — | Apr 5 – May 3 | May 30 |
| Bush beans | — | May 10 – May 31 | Jun 29 |
| Carrot | — | Apr 15 – May 27 | Jun 14 |
| Beet | — | Apr 15 – May 27 | Jun 4 |
| Potato | — | Apr 15 – May 6 | Jun 24 |
| Kale | Mar 1 – Mar 15 | Apr 12 – Apr 26 | May 25 |
| Broccoli | Feb 22 – Mar 8 | Apr 5 – Apr 26 | Jun 4 |
| Cucumber | Apr 19 – Apr 26 | May 17 – May 31 | Jul 6 |
| Summer squash and zucchini | Apr 19 – Apr 26 | May 17 – May 31 | Jul 1 |
| Winter squash | Apr 19 – Apr 26 | May 17 – May 31 | Aug 5 |
| Sweet corn | — | May 10 – May 31 | Jul 9 |
| Onion (from sets) | — | Apr 5 – Apr 26 | Jul 4 |
| Garlic | — | Sep 18 – Oct 16 (fall) | following summer |
| Spinach | — | Apr 5 – May 3 | May 13 |
| Basil | Apr 5 – Apr 19 | May 17 – May 31 | Jul 13 |
Hawarden'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 |
|---|---|
| 1938 | Apr 22 |
| 1939 | Apr 19 |
| 1940 | May 1 |
| 1941 | Apr 24 |
| 1942 | May 15 |
| 1943 | May 13 |
| 1944 | May 6 |
| 1945 | May 17 |
| 1946 | May 12 |
| 1947 | May 29 |
| 1949 | Apr 24 |
| 1950 | May 1 |
| 1951 | Apr 26 |
| 1952 | May 12 |
| 1953 | May 14 |
| 1954 | May 10 |
| 1955 | May 8 |
| 1956 | May 4 |
| 1957 | May 5 |
| 1958 | Apr 29 |
| 1959 | May 15 |
| 1960 | May 8 |
| 1961 | May 9 |
| 1962 | Apr 19 |
| 1963 | May 23 |
| 1964 | Apr 22 |
| 1965 | Apr 27 |
| 1966 | May 9 |
| 1967 | May 9 |
| 1968 | May 12 |
| 1969 | May 12 |
| 1970 | May 2 |
| 1971 | May 12 |
| 1972 | Apr 25 |
| 1973 | May 16 |
| 1974 | May 3 |
| 1975 | May 1 |
| 1976 | May 6 |
| 1977 | Apr 8 |
| 1978 | May 3 |
| 1979 | May 4 |
| 1980 | May 9 |
| 1981 | May 11 |
| 1982 | Apr 21 |
| 1983 | May 15 |
| 1984 | May 8 |
| 1985 | Apr 11 |
| 1986 | May 2 |
| 1987 | Apr 23 |
| 1988 | Apr 28 |
| 1989 | May 7 |
| 1990 | May 1 |
| 1991 | May 7 |
| 1992 | Apr 27 |
| 1993 | May 20 |
| 1994 | May 1 |
| 1995 | May 3 |
| 1996 | May 1 |
| 1997 | May 16 |
| 1998 | Apr 22 |
| 1999 | Apr 19 |
| 2001 | Apr 25 |
| 2002 | May 19 |
| 2003 | Apr 23 |
| 2004 | May 14 |
| 2005 | May 4 |
| 2006 | Apr 26 |
| 2007 | Apr 16 |
| 2008 | Apr 29 |
| 2009 | Apr 28 |
| 2010 | May 9 |
| 2011 | May 4 |
| 2012 | Apr 23 |
| 2013 | May 12 |
| 2014 | May 18 |
| 2015 | Apr 23 |
| 2016 | May 2 |
| 2017 | May 2 |
| 2018 | Apr 26 |
| 2019 | May 11 |
Each year's frost-free daysLong-term trend
See the data as a table
| Year | Frost-free days |
|---|---|
| 1938 | 149 |
| 1939 | 159 |
| 1940 | 133 |
| 1941 | 156 |
| 1942 | 131 |
| 1943 | 126 |
| 1944 | 155 |
| 1945 | 134 |
| 1946 | 151 |
| 1947 | 115 |
| 1949 | 151 |
| 1950 | 154 |
| 1951 | 154 |
| 1952 | 133 |
| 1953 | 130 |
| 1954 | 134 |
| 1955 | 125 |
| 1956 | 148 |
| 1957 | 165 |
| 1958 | 151 |
| 1959 | 145 |
| 1960 | 160 |
| 1961 | 141 |
| 1962 | 153 |
| 1963 | 157 |
| 1964 | 169 |
| 1965 | 149 |
| 1966 | 148 |
| 1967 | 141 |
| 1968 | 144 |
| 1969 | 148 |
| 1970 | 159 |
| 1971 | 129 |
| 1972 | 157 |
| 1974 | 122 |
| 1975 | 143 |
| 1976 | 144 |
| 1977 | 177 |
| 1978 | 156 |
| 1979 | 157 |
| 1980 | 139 |
| 1981 | 128 |
| 1982 | 177 |
| 1983 | 128 |
| 1984 | 140 |
| 1985 | 165 |
| 1986 | 127 |
| 1987 | 162 |
| 1988 | 158 |
| 1989 | 138 |
| 1990 | 144 |
| 1991 | 134 |
| 1992 | 154 |
| 1993 | 116 |
| 1994 | 176 |
| 1995 | 141 |
| 1996 | 154 |
| 1998 | 161 |
| 1999 | 154 |
| 2001 | 163 |
| 2002 | 130 |
| 2003 | 159 |
| 2004 | 140 |
| 2005 | 155 |
| 2006 | 146 |
| 2007 | 151 |
| 2008 | 167 |
| 2009 | 161 |
| 2010 | 158 |
| 2011 | 133 |
| 2012 | 152 |
| 2013 | 153 |
| 2014 | 138 |
| 2015 | 175 |
| 2016 | 163 |
| 2017 | 161 |
| 2018 | 160 |
| 2019 | 152 |
Each year's average temperature, April to SeptemberLong-term trend
See the data as a table
| Year | Growing-season temperature |
|---|---|
| 1938 | 19.1 °C |
| 1939 | 19.5 °C |
| 1940 | 18.4 °C |
| 1941 | 19.2 °C |
| 1942 | 18.3 °C |
| 1943 | 18.5 °C |
| 1944 | 18.3 °C |
| 1945 | 16.8 °C |
| 1946 | 18.2 °C |
| 1947 | 17.9 °C |
| 1949 | 19.0 °C |
| 1950 | 16.5 °C |
| 1951 | 16.6 °C |
| 1952 | 18.6 °C |
| 1953 | 18.1 °C |
| 1954 | 18.5 °C |
| 1955 | 20.7 °C |
| 1956 | 18.9 °C |
| 1957 | 18.2 °C |
| 1958 | 18.4 °C |
| 1959 | 19.2 °C |
| 1960 | 18.1 °C |
| 1961 | 17.5 °C |
| 1962 | 17.9 °C |
| 1963 | 19.6 °C |
| 1964 | 18.8 °C |
| 1965 | 17.9 °C |
| 1966 | 17.5 °C |
| 1967 | 17.6 °C |
| 1968 | 18.3 °C |
| 1969 | 17.9 °C |
| 1970 | 19.0 °C |
| 1971 | 18.3 °C |
| 1972 | 17.8 °C |
| 1973 | 18.4 °C |
| 1974 | 17.8 °C |
| 1975 | 18.1 °C |
| 1976 | 19.3 °C |
| 1977 | 20.1 °C |
| 1978 | 18.8 °C |
| 1979 | 17.8 °C |
| 1980 | 19.1 °C |
| 1981 | 18.7 °C |
| 1982 | 18.0 °C |
| 1983 | 18.8 °C |
| 1984 | 17.9 °C |
| 1985 | 18.4 °C |
| 1986 | 18.8 °C |
| 1987 | 19.5 °C |
| 1988 | 20.1 °C |
| 1989 | 18.2 °C |
| 1990 | 18.5 °C |
| 1991 | 19.1 °C |
| 1992 | 16.4 °C |
| 1993 | 15.9 °C |
| 1994 | 17.1 °C |
| 1995 | 16.4 °C |
| 1996 | 16.0 °C |
| 1997 | 16.4 °C |
| 1998 | 18.2 °C |
| 2001 | 17.9 °C |
| 2002 | 18.0 °C |
| 2003 | 17.1 °C |
| 2004 | 17.1 °C |
| 2005 | 18.5 °C |
| 2006 | 18.2 °C |
| 2007 | 18.6 °C |
| 2008 | 17.0 °C |
| 2009 | 16.5 °C |
| 2010 | 18.2 °C |
| 2011 | 17.5 °C |
| 2012 | 19.7 °C |
| 2013 | 17.1 °C |
| 2014 | 17.1 °C |
| 2015 | 18.2 °C |
| 2016 | 18.6 °C |
| 2017 | 18.0 °C |
| 2018 | 17.8 °C |
| 2019 | 17.7 °C |
What this means for you: Since 1938, Hawarden's last spring frost has stayed at about the same time of year. The frost-free season has grown by about 2 days per decade. Year-to-year swings are large, so keep using the safe date rather than the trend.
Source: daily records from Hawarden (NOAA GHCN-Daily). Years with too many missing days are left out.