When to plant in Walnut Creek, CA
Planting dates worked out from Walnut Creek's own frost records, not a generic zone chart.
Frost is rare in Walnut Creek: in 10 of the last 26 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 5
1 year in 10 has a later frost
Average last frost
Jan 14
about a 50% chance of a later one
Average first fall frost
Dec 17
1 year in 10 by Nov 27
Frost-free days
338
median, 1991–2020
Station used: Concord Wwtp · 8.6 km away · station 12 m, town 52 m. How we match towns to stations
Walnut Creek'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 |
|---|---|
| 1992 | Jan 13 |
| 1993 | Jan 11 |
| 1997 | Jan 14 |
| 1999 | Jan 24 |
| 2001 | Jan 18 |
| 2002 | Jan 31 |
| 2003 | Feb 9 |
| 2004 | Jan 5 |
| 2007 | Jan 24 |
| 2009 | Jan 18 |
| 2011 | Feb 26 |
| 2012 | Jan 17 |
| 2013 | Jan 20 |
| 2015 | Jan 3 |
| 2017 | Jan 6 |
| 2018 | Feb 20 |
Each year's frost-free daysLong-term trend
See the data as a table
| Year | Frost-free days |
|---|---|
| 1992 | 338 |
| 1993 | 345 |
| 1994 | 321 |
| 1995 | 363 |
| 1996 | 363 |
| 1997 | 331 |
| 1998 | 353 |
| 1999 | 340 |
| 2001 | 346 |
| 2002 | 333 |
| 2003 | 320 |
| 2004 | 328 |
| 2005 | 363 |
| 2006 | 350 |
| 2007 | 331 |
| 2008 | 352 |
| 2009 | 323 |
| 2010 | 327 |
| 2011 | 294 |
| 2013 | 318 |
| 2014 | 363 |
| 2015 | 329 |
| 2016 | 349 |
| 2017 | 350 |
| 2018 | 313 |
Each year's average temperature, April to SeptemberLong-term trend
See the data as a table
| Year | Growing-season temperature |
|---|---|
| 1992 | 21.1 °C |
| 1993 | 20.7 °C |
| 1995 | 20.3 °C |
| 1996 | 21.2 °C |
| 1997 | 21.5 °C |
| 2002 | 20.2 °C |
| 2003 | 20.2 °C |
| 2004 | 20.9 °C |
| 2005 | 20.0 °C |
| 2010 | 19.3 °C |
| 2011 | 19.9 °C |
| 2013 | 21.1 °C |
| 2014 | 21.4 °C |
| 2015 | 21.1 °C |
| 2016 | 21.1 °C |
| 2017 | 21.4 °C |
| 2018 | 20.7 °C |
What this means for you: This station's record is too short to show a reliable trend yet.
Source: daily records from Concord Wwtp (NOAA GHCN-Daily). Years with too many missing days are left out.