When to plant in Sammamish, WA
Planting dates worked out from Sammamish's own frost records, not a generic zone chart.
Safe to plant out
Mar 27
1 year in 10 has a later frost
Average last frost
Mar 7
about a 50% chance of a later one
Average first fall frost
Nov 21
1 year in 10 by Oct 31
Frost-free days
250
median, 1991–2020
Station used: Seattle Sand Pt Wfo · 14.0 km away · station 18 m, town 18 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 5 – Mar 19 | Apr 30 – May 14 | Jun 24 |
| Sweet pepper | Feb 19 – Mar 5 | Apr 30 – May 14 | Jun 29 |
| Lettuce (leaf) | Jan 3 – Jan 10 | Feb 7 – Feb 21 | Mar 19 |
| Peas | — | Jan 28 – Feb 25 | Mar 24 |
| Bush beans | — | Apr 21 – May 12 | Jun 10 |
| Carrot | — | Mar 15 – Apr 26 | May 14 |
| Beet | — | Mar 15 – Apr 26 | May 4 |
| Potato | — | Mar 15 – Apr 5 | May 24 |
| Kale | Dec 27 – Jan 10 | Feb 7 – Feb 21 | Mar 22 |
| Broccoli | Dec 27 – Jan 10 | Feb 7 – Feb 28 | Apr 8 |
| Cucumber | Apr 2 – Apr 9 | Apr 30 – May 14 | Jun 19 |
| Summer squash and zucchini | Apr 2 – Apr 9 | Apr 30 – May 14 | Jun 14 |
| Winter squash | Apr 2 – Apr 9 | Apr 30 – May 14 | Jul 19 |
| Sweet corn | — | Apr 21 – May 12 | Jun 20 |
| Onion (from sets) | — | Feb 7 – Feb 28 | May 8 |
| Garlic | — | Oct 17 – Nov 14 (fall) | following summer |
| Spinach | — | Jan 28 – Feb 25 | Mar 7 |
| Basil | Mar 19 – Apr 2 | Apr 30 – May 14 | Jun 26 |
Sammamish'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 |
|---|---|
| 1987 | Feb 25 |
| 1988 | Mar 11 |
| 1990 | Mar 12 |
| 1991 | Apr 11 |
| 1992 | Jan 20 |
| 1993 | Feb 28 |
| 1994 | Feb 9 |
| 1995 | Mar 3 |
| 1996 | Mar 25 |
| 1997 | Feb 28 |
| 1998 | Mar 7 |
| 2000 | Mar 20 |
| 2001 | Mar 22 |
| 2002 | Mar 8 |
| 2003 | Feb 26 |
| 2004 | Feb 13 |
| 2005 | Feb 24 |
| 2006 | Mar 19 |
| 2007 | Mar 21 |
| 2008 | Apr 3 |
| 2009 | Apr 4 |
| 2010 | Mar 9 |
| 2011 | Mar 4 |
| 2012 | Mar 7 |
| 2013 | Mar 24 |
| 2014 | Mar 22 |
| 2015 | Mar 4 |
| 2016 | Jan 15 |
| 2017 | Feb 27 |
| 2018 | Mar 4 |
| 2019 | Mar 11 |
| 2020 | Mar 18 |
| 2021 | Mar 30 |
| 2022 | Mar 10 |
| 2024 | Mar 7 |
Each year's frost-free daysLong-term trend
See the data as a table
| Year | Frost-free days |
|---|---|
| 1987 | 290 |
| 1988 | 278 |
| 1990 | 280 |
| 1991 | 201 |
| 1992 | 308 |
| 1993 | 266 |
| 1994 | 281 |
| 1995 | 276 |
| 2000 | 235 |
| 2001 | 275 |
| 2002 | 235 |
| 2003 | 247 |
| 2004 | 288 |
| 2005 | 276 |
| 2006 | 224 |
| 2007 | 245 |
| 2008 | 253 |
| 2009 | 242 |
| 2010 | 257 |
| 2011 | 246 |
| 2012 | 246 |
| 2013 | 240 |
| 2014 | 234 |
| 2015 | 263 |
| 2016 | 324 |
| 2017 | 248 |
| 2018 | 260 |
| 2019 | 262 |
| 2020 | 234 |
| 2021 | 270 |
| 2022 | 243 |
| 2024 | 270 |
Each year's average temperature, April to SeptemberLong-term trend
See the data as a table
| Year | Growing-season temperature |
|---|---|
| 1987 | 16.2 °C |
| 1988 | 15.5 °C |
| 1989 | 15.9 °C |
| 1991 | 15.2 °C |
| 1992 | 16.3 °C |
| 1993 | 16.2 °C |
| 1994 | 16.4 °C |
| 1995 | 16.2 °C |
| 1996 | 15.3 °C |
| 1997 | 16.2 °C |
| 2000 | 15.4 °C |
| 2001 | 15.0 °C |
| 2002 | 15.3 °C |
| 2003 | 16.2 °C |
| 2004 | 16.7 °C |
| 2005 | 16.0 °C |
| 2006 | 15.9 °C |
| 2007 | 15.7 °C |
| 2008 | 14.9 °C |
| 2009 | 16.2 °C |
| 2010 | 15.1 °C |
| 2011 | 15.0 °C |
| 2012 | 15.6 °C |
| 2013 | 16.6 °C |
| 2014 | 17.2 °C |
| 2015 | 17.2 °C |
| 2016 | 17.1 °C |
| 2017 | 16.8 °C |
| 2018 | 16.9 °C |
| 2019 | 16.5 °C |
| 2020 | 16.5 °C |
| 2021 | 17.0 °C |
| 2022 | 16.4 °C |
| 2024 | 16.5 °C |
What this means for you: Since 1987, Sammamish's last spring frost has come about 2 days later per decade, on average. The frost-free season has shrunk 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 Seattle Sand Pt Wfo (NOAA GHCN-Daily). Years with too many missing days are left out.