When to plant in Alta Sierra (near Grass Valley), CA
Planting dates worked out from Alta Sierra (near Grass Valley)'s own frost records, not a generic zone chart.
Safe to plant out
May 3
1 year in 10 has a later frost
Average last frost
Apr 14
about a 50% chance of a later one
Average first fall frost
Nov 12
1 year in 10 by Oct 27
Frost-free days
215
median, 1991–2020
Station used: Grass Valley #2 · 7.1 km away · station 732 m, town 704 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 8 – Mar 22 | May 3 – May 17 | Jun 27 |
| Sweet pepper | Feb 22 – Mar 8 | May 3 – May 17 | Jul 2 |
| Lettuce (leaf) | Feb 10 – Feb 17 | Mar 17 – Mar 31 | Apr 26 |
| Peas | — | Mar 3 – Mar 31 | Apr 27 |
| Bush beans | — | Apr 26 – May 17 | Jun 15 |
| Carrot | — | Mar 24 – May 5 | May 23 |
| Beet | — | Mar 17 – Apr 28 | May 6 |
| Potato | — | Mar 24 – Apr 14 | Jun 2 |
| Kale | Feb 3 – Feb 17 | Mar 17 – Mar 31 | Apr 29 |
| Broccoli | Feb 3 – Feb 17 | Mar 17 – Apr 7 | May 16 |
| Cucumber | Apr 5 – Apr 12 | May 3 – May 17 | Jun 22 |
| Summer squash and zucchini | Apr 5 – Apr 12 | May 3 – May 17 | Jun 17 |
| Winter squash | Apr 5 – Apr 12 | May 3 – May 17 | Jul 22 |
| Sweet corn | — | Apr 26 – May 17 | Jun 25 |
| Onion (from sets) | — | Mar 17 – Apr 7 | Jun 15 |
| Garlic | — | Oct 28 – Nov 25 (fall) | following summer |
| Spinach | — | Mar 3 – Mar 31 | Apr 10 |
| Basil | Mar 22 – Apr 5 | May 3 – May 17 | Jun 29 |
Alta Sierra (near Grass Valley)'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 |
|---|---|
| 1967 | May 1 |
| 1968 | Apr 21 |
| 1969 | Apr 25 |
| 1970 | Apr 29 |
| 1971 | Apr 22 |
| 1972 | Apr 13 |
| 1973 | Apr 18 |
| 1974 | May 19 |
| 1975 | May 5 |
| 1976 | Apr 25 |
| 1977 | May 17 |
| 1978 | Apr 22 |
| 1979 | May 9 |
| 1980 | Apr 15 |
| 1981 | Apr 12 |
| 1982 | Apr 18 |
| 1983 | May 9 |
| 1984 | Apr 28 |
| 1985 | Mar 30 |
| 1986 | May 7 |
| 1987 | Apr 19 |
| 1988 | May 1 |
| 1989 | Apr 27 |
| 1990 | Mar 14 |
| 1991 | Apr 16 |
| 1992 | Mar 10 |
| 1993 | Apr 12 |
| 1994 | Apr 26 |
| 1995 | Apr 21 |
| 1996 | Mar 29 |
| 1997 | Apr 5 |
| 1998 | Apr 16 |
| 1999 | Apr 10 |
| 2000 | May 11 |
| 2001 | Apr 12 |
| 2002 | Apr 19 |
| 2003 | Apr 15 |
| 2004 | Mar 4 |
| 2005 | Apr 15 |
| 2008 | Apr 30 |
| 2009 | Apr 29 |
| 2010 | May 23 |
| 2011 | May 15 |
| 2012 | Apr 7 |
| 2013 | Apr 17 |
| 2014 | Apr 3 |
| 2015 | Apr 8 |
| 2016 | Mar 29 |
| 2017 | Apr 15 |
| 2018 | Apr 19 |
| 2019 | Apr 11 |
| 2020 | Apr 3 |
| 2021 | Mar 25 |
| 2022 | May 12 |
| 2023 | Apr 20 |
| 2024 | Apr 8 |
| 2025 | Apr 4 |
| 2026 | Mar 7 |
Each year's frost-free daysLong-term trend
See the data as a table
| Year | Frost-free days |
|---|---|
| 1967 | 158 |
| 1968 | 205 |
| 1969 | 171 |
| 1970 | 180 |
| 1971 | 177 |
| 1972 | 198 |
| 1973 | 199 |
| 1974 | 187 |
| 1975 | 170 |
| 1976 | 214 |
| 1977 | 172 |
| 1978 | 192 |
| 1979 | 172 |
| 1980 | 210 |
| 1981 | 182 |
| 1982 | 191 |
| 1983 | 182 |
| 1984 | 172 |
| 1985 | 196 |
| 1987 | 209 |
| 1988 | 199 |
| 1989 | 194 |
| 1990 | 232 |
| 1991 | 196 |
| 1992 | 243 |
| 1993 | 214 |
| 1994 | 189 |
| 1995 | 238 |
| 1996 | 204 |
| 1997 | 240 |
| 1998 | 206 |
| 1999 | 225 |
| 2001 | 227 |
| 2002 | 195 |
| 2003 | 199 |
| 2004 | 236 |
| 2008 | 163 |
| 2009 | 181 |
| 2010 | 156 |
| 2011 | 173 |
| 2012 | 217 |
| 2013 | 220 |
| 2014 | 265 |
| 2015 | 209 |
| 2016 | 232 |
| 2017 | 216 |
| 2018 | 203 |
| 2019 | 227 |
| 2020 | 219 |
| 2021 | 243 |
| 2022 | 174 |
| 2023 | 192 |
| 2024 | 221 |
| 2025 | 240 |
Each year's average temperature, April to SeptemberLong-term trend
See the data as a table
| Year | Growing-season temperature |
|---|---|
| 1967 | 17.7 °C |
| 1968 | 17.9 °C |
| 1969 | 18.4 °C |
| 1970 | 18.4 °C |
| 1971 | 17.6 °C |
| 1972 | 18.1 °C |
| 1973 | 18.7 °C |
| 1974 | 18.3 °C |
| 1975 | 17.5 °C |
| 1976 | 16.5 °C |
| 1977 | 17.2 °C |
| 1978 | 16.4 °C |
| 1979 | 17.3 °C |
| 1980 | 16.3 °C |
| 1981 | 18.2 °C |
| 1982 | 16.3 °C |
| 1983 | 16.4 °C |
| 1984 | 17.8 °C |
| 1985 | 17.3 °C |
| 1986 | 17.0 °C |
| 1987 | 17.9 °C |
| 1988 | 17.7 °C |
| 1989 | 17.0 °C |
| 1990 | 18.1 °C |
| 1991 | 17.3 °C |
| 1992 | 19.1 °C |
| 1993 | 17.2 °C |
| 1994 | 18.1 °C |
| 1995 | 17.1 °C |
| 1996 | 18.5 °C |
| 1997 | 18.5 °C |
| 1998 | 16.8 °C |
| 1999 | 17.4 °C |
| 2000 | 18.1 °C |
| 2001 | 18.9 °C |
| 2002 | 18.6 °C |
| 2003 | 18.1 °C |
| 2004 | 18.6 °C |
| 2005 | 17.8 °C |
| 2008 | 18.9 °C |
| 2009 | 18.8 °C |
| 2010 | 16.9 °C |
| 2011 | 17.3 °C |
| 2012 | 18.8 °C |
| 2013 | 19.0 °C |
| 2014 | 19.4 °C |
| 2015 | 19.2 °C |
| 2016 | 19.1 °C |
| 2017 | 19.5 °C |
| 2018 | 19.1 °C |
| 2019 | 18.4 °C |
| 2020 | 19.6 °C |
| 2021 | 20.6 °C |
| 2022 | 19.2 °C |
| 2023 | 18.5 °C |
| 2024 | 19.9 °C |
| 2025 | 19.2 °C |
| 2026 | 18.8 °C |
What this means for you: Since 1967, Alta Sierra (near Grass Valley)'s last spring frost has come about 3 days earlier per decade, on average. The frost-free season has grown by about 6 days per decade. Year-to-year swings are large, so keep using the safe date rather than the trend.
Source: daily records from Grass Valley #2 (NOAA GHCN-Daily). Years with too many missing days are left out.