When to plant in Chelmsford, MA

Planting dates worked out from Chelmsford's own frost records, not a generic zone chart.

Safe to plant out

May 12

1 year in 10 has a later frost

Average last frost

Apr 29

about a 50% chance of a later one

Average first fall frost

Oct 11

1 year in 10 by Sep 26

Frost-free days

164

median, 1991–2020

Station used: Lowell · 4.6 km away · station 34 m, town 75 m. How we match towns to stations

This season

Plan your garden.

Build my Chelmsford plan

Planting dates for common crops

Crop	Start indoors	Plant out or sow	Harvest from
Tomato	Mar 17 – Mar 31	May 12 – May 26	Jul 6
Sweet pepper	Mar 3 – Mar 17	May 12 – May 26	Jul 11
Lettuce (leaf)	Mar 2 – Mar 9	Apr 6 – Apr 20	May 16
Peas	—	Apr 6 – May 4	May 31
Bush beans	—	May 5 – May 26	Jun 24
Carrot	—	Apr 15 – May 27	Jun 14
Beet	—	Apr 15 – May 27	Jun 4
Potato	—	Apr 15 – May 6	Jun 24
Kale	Mar 2 – Mar 16	Apr 13 – Apr 27	May 26
Broccoli	Feb 23 – Mar 9	Apr 6 – Apr 27	Jun 5
Cucumber	Apr 14 – Apr 21	May 12 – May 26	Jul 1
Summer squash and zucchini	Apr 14 – Apr 21	May 12 – May 26	Jun 26
Winter squash	Apr 14 – Apr 21	May 12 – May 26	Jul 31
Sweet corn	—	May 5 – May 26	Jul 4
Onion (from sets)	—	Apr 6 – Apr 27	Jul 5
Garlic	—	Sep 27 – Oct 25 (fall)	following summer
Spinach	—	Apr 6 – May 4	May 14
Basil	Mar 31 – Apr 14	May 12 – May 26	Jul 8

Plan all 65 crops for Chelmsford

Chelmsford'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
1889	Apr 23
1890	Apr 29
1891	May 19
1892	May 2
1893	Apr 26
1894	Apr 16
1895	May 2
1896	May 8
1897	Apr 22
1898	May 10
1899	May 4
1900	May 11
1901	Apr 28
1902	May 10
1903	May 3
1904	Apr 23
1905	Apr 24
1906	Apr 27
1907	May 12
1908	May 2
1909	Apr 29
1910	Apr 29
1911	May 5
1912	May 1
1913	Apr 21
1914	Apr 24
1915	Apr 22
1916	Apr 16
1917	May 4
1918	Apr 26
1919	Apr 27
1920	May 5
1921	May 12
1922	May 1
1923	May 11
1924	Apr 29
1925	Apr 22
1926	May 5
1927	Apr 26
1928	Apr 27
1929	Apr 24
1931	May 1
1943	Apr 18
1944	Apr 29
1945	Apr 23
1946	Apr 18
1947	May 15
1948	Apr 26
1949	Apr 25
1950	Apr 30
1951	Apr 21
1952	Apr 17
1953	Apr 14
1954	Apr 10
1955	Apr 17
1956	May 25
1957	Apr 16
1958	Apr 10
1959	Apr 24
1960	Apr 20
1961	May 3
1962	Apr 25
1963	Apr 14
1964	May 2
1965	Apr 25
1966	May 3
1967	Apr 26
1968	Apr 28
1969	Apr 21
1970	Apr 20
1990	Apr 20
1991	Apr 20
1992	May 8
1993	Apr 30
1994	Apr 24
1995	May 2
1996	May 15
1997	Apr 17
1998	Apr 27
1999	Apr 15
2000	Apr 15
2001	May 8
2002	Apr 28
2003	May 18
2005	May 13
2007	Apr 21
2008	May 3
2009	Apr 21
2010	May 11
2011	Apr 23
2012	May 1
2013	Apr 23
2014	Apr 22
2015	Apr 26
2016	Apr 29
2018	Apr 24
2019	Apr 30
2020	Apr 30
2024	Apr 27
2025	Apr 19

Each year's frost-free daysLong-term trend

See the data as a table

Year	Frost-free days
1889	170
1890	148
1891	145
1892	152
1893	173
1894	203
1895	160
1896	154
1897	164
1898	160
1899	150
1900	161
1902	160
1903	171
1904	151
1905	180
1906	167
1907	149
1908	163
1909	173
1910	182
1911	155
1912	172
1913	184
1914	157
1915	171
1916	184
1917	142
1918	164
1919	163
1920	180
1921	166
1922	165
1923	148
1924	167
1925	156
1926	163
1928	157
1929	167
1943	175
1944	169
1945	163
1946	186
1947	130
1948	172
1949	182
1950	147
1951	161
1952	185
1953	162
1954	180
1955	188
1956	138
1957	205
1958	185
1959	173
1960	184
1961	165
1963	178
1964	156
1965	155
1966	176
1967	186
1968	184
1969	184
1970	182
1990	183
1991	162
1992	145
1993	142
1994	162
1995	131
1996	142
1997	184
1998	162
1999	175
2000	166
2001	153
2002	169
2005	161
2007	190
2008	167
2009	173
2010	160
2011	187
2012	164
2013	185
2014	195
2015	174
2016	165
2018	177
2019	158
2020	162
2024	172
2025	174

Each year's average temperature, April to SeptemberLong-term trend

See the data as a table

Year	Growing-season temperature
1889	16.9 °C
1890	16.1 °C
1891	16.2 °C
1892	17.1 °C
1893	16.1 °C
1894	17.4 °C
1895	17.3 °C
1896	17.5 °C
1897	16.6 °C
1898	17.1 °C
1899	17.1 °C
1900	17.3 °C
1902	16.7 °C
1904	17.2 °C
1905	17.2 °C
1906	18.0 °C
1907	16.5 °C
1908	18.3 °C
1909	17.1 °C
1910	17.8 °C
1911	18.2 °C
1912	17.2 °C
1913	17.4 °C
1914	17.0 °C
1915	17.2 °C
1916	16.9 °C
1917	16.2 °C
1918	17.1 °C
1919	17.2 °C
1920	16.4 °C
1921	18.2 °C
1922	17.6 °C
1923	17.0 °C
1924	16.2 °C
1925	17.8 °C
1926	16.4 °C
1927	16.6 °C
1928	16.4 °C
1943	17.1 °C
1944	18.0 °C
1945	17.7 °C
1946	17.1 °C
1947	17.5 °C
1948	17.9 °C
1949	19.3 °C
1950	17.6 °C
1951	18.0 °C
1952	18.8 °C
1953	18.5 °C
1954	17.4 °C
1955	19.2 °C
1956	17.1 °C
1957	18.9 °C
1958	17.9 °C
1959	19.1 °C
1960	18.4 °C
1961	17.6 °C
1962	16.3 °C
1963	17.1 °C
1964	17.1 °C
1965	17.5 °C
1966	17.2 °C
1967	16.9 °C
1968	17.7 °C
1969	18.2 °C
1970	17.6 °C
1987	16.9 °C
1991	17.2 °C
1992	15.8 °C
1993	17.2 °C
1994	17.1 °C
1995	16.6 °C
1996	16.9 °C
1997	16.3 °C
1998	17.7 °C
2000	16.4 °C
2001	17.8 °C
2002	17.7 °C
2005	17.7 °C
2007	17.2 °C
2008	17.2 °C
2009	16.9 °C
2010	18.8 °C
2011	17.6 °C
2012	17.8 °C
2013	17.4 °C
2014	16.7 °C
2015	17.7 °C
2016	17.4 °C
2018	18.3 °C
2019	17.7 °C
2020	18.1 °C
2021	18.6 °C
2024	18.4 °C
2025	18.5 °C

What this means for you: Since 1889, Chelmsford'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 Lowell (NOAA GHCN-Daily). Years with too many missing days are left out.

Nearby towns

Lowell Westford Carlisle Billerica Dracut Tyngsboro