Our first frosts are approaching! Soon we’ll be crunch crunching through the grass and scraping off our windshields in the morning.
The average first frost date is just that – an average – so it’s a good idea to familiarize yourself with the norms for your area and plan accordingly. Frosts can occur much earlier or later than typical.
There are a number of factors that contribute to frost and temperatures can vary by neighborhood or even block to block. For instance the average first frost in downtown Portland is typically three weeks after the first frost at the Portland Airport. In outlying areas like Canby and Forest Grove the average first frost is usually in mid-October.
|City||Average First Frost/Last Frost|
|Beaverton||November 2/April 14|
|Canby||October 30/May 1|
|Forest Grove||October 19/April 26|
|Hillsboro||October 23/April 26|
|Newberg||November 20/April 6|
|Oregon City||November 6/April 3|
|Portland Airport||November 6/March 28|
|Portland Downtown||November 27/February 24|
|Troutdale||November 8/March 28|
|Wilsonville||October 30/April 18|
Statistics used to formulate first and last frost dates are drawn from weather data collected from 1981-2010. All data is collected at low elevations. Chart source info is from the Oregon Climate Service at OSU.
Learn more on the Master Gardener Spring Problems Page.