When to plant in Los Altos, CA

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

Frost is rare in Los Altos: in 11 of the last 25 springs there was none at all. Frost dates matter less here than heat, so the planting table below is left out.

Safe to plant out

Feb 11

1 year in 10 has a later frost

Average last frost

Jan 12

about a 50% chance of a later one

Average first fall frost

Dec 21

1 year in 10 by Nov 30

Frost-free days

348

median, 1991–2020

Station used: Moffett Fed Airfield · 6.3 km away · station 12 m, town 48 m. How we match towns to stations

Los Altos'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
1945	Apr 5
1946	Feb 14
1947	Jan 31
1948	Mar 11
1949	Feb 14
1950	Mar 13
1951	Mar 11
1952	Jan 9
1953	Mar 3
1954	Jan 25
1955	Mar 17
1956	Feb 18
1957	Feb 4
1959	Jan 4
1960	Jan 5
1961	Jan 18
1962	Feb 27
1963	Jan 21
1966	Jan 21
1968	Jan 6
1972	Jan 5
1975	Jan 30
1988	Feb 2
1989	Feb 7
1990	Feb 15
1993	Jan 4
2002	Feb 4
2004	Jan 4
2005	Jan 14
2006	Feb 16
2007	Jan 24
2009	Jan 4
2011	Feb 27
2012	Jan 18
2013	Jan 16
2015	Jan 3
2017	Jan 6
2018	Feb 24
2019	Jan 2

Each year's frost-free daysLong-term trend

See the data as a table

Year	Frost-free days
1945	251
1946	269
1947	283
1948	260
1949	300
1950	292
1951	271
1952	355
1953	302
1954	329
1955	286
1956	293
1957	329
1958	319
1959	360
1960	359
1961	346
1962	300
1963	324
1964	363
1965	349
1966	340
1967	363
1968	348
1969	363
1970	363
1971	363
1972	336
1973	363
1974	363
1975	334
1976	331
1977	363
1978	340
1979	363
1980	363
1981	363
1982	363
1983	363
1984	363
1985	344
1986	363
1987	363
1988	331
1989	326
1990	308
1991	363
1992	363
1993	360
1999	363
2000	363
2001	363
2002	329
2003	325
2004	333
2005	350
2006	304
2007	331
2008	350
2010	328
2011	306
2012	346
2013	322
2014	363
2015	329
2016	350
2017	349
2018	309

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

See the data as a table

Year	Growing-season temperature
1945	17.0 °C
1946	16.6 °C
1947	17.6 °C
1948	16.1 °C
1949	16.6 °C
1950	16.8 °C
1951	16.2 °C
1952	17.0 °C
1953	16.5 °C
1954	16.7 °C
1955	15.5 °C
1956	16.0 °C
1957	17.1 °C
1958	17.5 °C
1959	17.2 °C
1960	16.8 °C
1961	17.0 °C
1962	16.4 °C
1963	16.7 °C
1964	16.2 °C
1965	16.2 °C
1966	17.4 °C
1967	16.7 °C
1968	17.4 °C
1969	19.0 °C
1970	16.6 °C
1971	17.3 °C
1972	17.5 °C
1973	18.4 °C
1974	17.6 °C
1975	15.9 °C
1976	18.2 °C
1977	18.0 °C
1978	18.8 °C
1979	19.0 °C
1980	17.6 °C
1981	18.7 °C
1982	17.7 °C
1983	18.8 °C
1984	19.3 °C
1985	18.7 °C
1986	18.4 °C
1987	18.9 °C
1988	18.6 °C
1989	18.9 °C
1990	19.3 °C
1991	18.1 °C
1992	20.0 °C
1993	19.7 °C
1999	17.0 °C
2000	18.2 °C
2001	18.1 °C
2002	18.0 °C
2003	18.3 °C
2004	18.9 °C
2005	18.0 °C
2006	18.4 °C
2007	18.1 °C
2008	18.4 °C
2009	18.7 °C
2010	17.4 °C
2011	17.9 °C
2012	17.8 °C
2013	19.0 °C
2014	19.4 °C
2015	19.0 °C
2016	18.9 °C
2017	19.2 °C

What this means for you: Since 1945, Los Altos's last spring frost has come about 4 days earlier per decade, on average. The frost-free season has grown by about 5 days per decade. Year-to-year swings are large, so keep using the safe date rather than the trend.

Source: daily records from Moffett Fed Airfield (NOAA GHCN-Daily). Years with too many missing days are left out.

Nearby towns

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