When to plant in Thompson, CT
Planting dates worked out from Thompson's own frost records, not a generic zone chart.
Safe to plant out
May 11
1 year in 10 has a later frost
Average last frost
Apr 28
about a 50% chance of a later one
Average first fall frost
Oct 16
1 year in 10 by Oct 2
Frost-free days
168
median, 1991–2020
Station used: N Foster 1 E · 15.6 km away · station 192 m, town 181 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 16 – Mar 30 | May 11 – May 25 | Jul 5 |
| Sweet pepper | Mar 2 – Mar 16 | May 11 – May 25 | Jul 10 |
| Lettuce (leaf) | Feb 27 – Mar 6 | Apr 3 – Apr 17 | May 13 |
| Peas | — | Apr 3 – May 1 | May 28 |
| Bush beans | — | May 4 – May 25 | Jun 23 |
| Carrot | — | Apr 12 – May 24 | Jun 11 |
| Beet | — | Apr 12 – May 24 | Jun 1 |
| Potato | — | Apr 12 – May 3 | Jun 21 |
| Kale | Feb 27 – Mar 13 | Apr 10 – Apr 24 | May 23 |
| Broccoli | Feb 20 – Mar 6 | Apr 3 – Apr 24 | Jun 2 |
| Cucumber | Apr 13 – Apr 20 | May 11 – May 25 | Jun 30 |
| Summer squash and zucchini | Apr 13 – Apr 20 | May 11 – May 25 | Jun 25 |
| Winter squash | Apr 13 – Apr 20 | May 11 – May 25 | Jul 30 |
| Sweet corn | — | May 4 – May 25 | Jul 3 |
| Onion (from sets) | — | Apr 3 – Apr 24 | Jul 2 |
| Garlic | — | Oct 2 – Oct 30 (fall) | following summer |
| Spinach | — | Apr 3 – May 1 | May 11 |
| Basil | Mar 30 – Apr 13 | May 11 – May 25 | Jul 7 |
Thompson'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 |
|---|---|
| 1975 | Apr 30 |
| 1976 | May 4 |
| 1977 | May 10 |
| 1978 | May 4 |
| 1979 | Apr 22 |
| 1980 | Apr 22 |
| 1981 | May 9 |
| 1982 | Apr 23 |
| 1983 | May 10 |
| 1984 | Apr 22 |
| 1985 | May 9 |
| 1986 | May 4 |
| 1987 | May 14 |
| 1988 | Apr 23 |
| 1989 | Apr 25 |
| 1990 | Apr 19 |
| 1991 | Apr 19 |
| 1992 | May 7 |
| 1993 | Apr 29 |
| 1994 | Apr 23 |
| 1995 | Apr 18 |
| 1996 | May 14 |
| 1997 | May 8 |
| 1998 | Apr 12 |
| 1999 | Apr 25 |
| 2000 | Apr 28 |
| 2001 | May 7 |
| 2002 | May 19 |
| 2003 | Apr 25 |
| 2004 | Apr 17 |
| 2005 | Apr 22 |
| 2006 | Apr 29 |
| 2007 | May 7 |
| 2008 | May 1 |
| 2009 | Apr 20 |
| 2010 | May 11 |
| 2011 | Apr 22 |
| 2012 | Apr 28 |
| 2013 | Apr 22 |
| 2014 | Apr 21 |
| 2015 | May 2 |
| 2016 | Apr 27 |
| 2017 | Apr 9 |
| 2018 | Apr 21 |
| 2019 | Apr 29 |
| 2020 | May 13 |
| 2021 | Apr 23 |
| 2022 | Apr 29 |
| 2023 | May 18 |
| 2024 | Apr 26 |
| 2025 | Apr 18 |
Each year's frost-free daysLong-term trend
See the data as a table
| Year | Frost-free days |
|---|---|
| 1975 | 182 |
| 1976 | 158 |
| 1977 | 166 |
| 1978 | 156 |
| 1979 | 170 |
| 1980 | 170 |
| 1981 | 154 |
| 1982 | 171 |
| 1983 | 162 |
| 1984 | 166 |
| 1985 | 155 |
| 1986 | 155 |
| 1987 | 143 |
| 1988 | 166 |
| 1989 | 167 |
| 1990 | 183 |
| 1991 | 177 |
| 1992 | 146 |
| 1993 | 154 |
| 1994 | 162 |
| 1995 | 195 |
| 1996 | 142 |
| 1997 | 146 |
| 1998 | 192 |
| 1999 | 164 |
| 2000 | 153 |
| 2001 | 153 |
| 2002 | 148 |
| 2003 | 160 |
| 2004 | 200 |
| 2005 | 187 |
| 2006 | 167 |
| 2007 | 158 |
| 2008 | 170 |
| 2009 | 176 |
| 2010 | 151 |
| 2011 | 188 |
| 2012 | 167 |
| 2013 | 184 |
| 2014 | 181 |
| 2015 | 168 |
| 2016 | 180 |
| 2017 | 212 |
| 2018 | 179 |
| 2019 | 186 |
| 2020 | 169 |
| 2021 | 193 |
| 2022 | 173 |
| 2023 | 166 |
| 2024 | 173 |
Each year's average temperature, April to SeptemberLong-term trend
See the data as a table
| Year | Growing-season temperature |
|---|---|
| 1975 | 16.0 °C |
| 1976 | 16.3 °C |
| 1977 | 16.2 °C |
| 1978 | 15.5 °C |
| 1979 | 16.4 °C |
| 1980 | 16.6 °C |
| 1981 | 16.6 °C |
| 1982 | 15.6 °C |
| 1983 | 16.8 °C |
| 1984 | 16.2 °C |
| 1985 | 16.3 °C |
| 1986 | 15.9 °C |
| 1987 | 16.2 °C |
| 1988 | 16.5 °C |
| 1989 | 16.5 °C |
| 1990 | 16.4 °C |
| 1991 | 17.5 °C |
| 1992 | 15.6 °C |
| 1993 | 17.0 °C |
| 1994 | 17.1 °C |
| 1995 | 16.4 °C |
| 1996 | 16.4 °C |
| 1997 | 16.1 °C |
| 1998 | 17.4 °C |
| 1999 | 17.8 °C |
| 2000 | 16.1 °C |
| 2001 | 17.4 °C |
| 2002 | 17.1 °C |
| 2003 | 16.2 °C |
| 2004 | 16.5 °C |
| 2005 | 17.1 °C |
| 2006 | 16.7 °C |
| 2007 | 16.5 °C |
| 2008 | 16.7 °C |
| 2009 | 16.2 °C |
| 2010 | 17.7 °C |
| 2011 | 17.5 °C |
| 2012 | 17.4 °C |
| 2013 | 17.1 °C |
| 2014 | 16.4 °C |
| 2015 | 17.4 °C |
| 2016 | 17.3 °C |
| 2017 | 16.9 °C |
| 2018 | 17.4 °C |
| 2019 | 16.8 °C |
| 2020 | 17.1 °C |
| 2021 | 17.4 °C |
| 2022 | 17.4 °C |
| 2023 | 17.1 °C |
| 2024 | 17.3 °C |
What this means for you: Since 1975, Thompson's last spring frost has come about 1 day earlier per decade, on average. The frost-free season has grown by about 4 days per decade. Year-to-year swings are large, so keep using the safe date rather than the trend.
Source: daily records from N Foster 1 E (NOAA GHCN-Daily). Years with too many missing days are left out.