Now that is officially spring, when is the last frost in western WA?

The warm sunny Easter weekend had many gardeners itching to get into their yards and begin putting seasonal plants outside in pots and flower beds. Many stores are offering seasonals right now, a great temptation to buy and put them in the ground. But is the threat of frost gone? In short, not yet.

Any clear skies this month also means nights can dip to freezing, as it did on this past weekend’s Saturday morning in the South Sound, some areas in southwest Washington, and in parts of the North Sound.

Looking at local historical weather records for western Washington, the odds of freezing weather diminish around the last week of April in more urban areas like Seattle, Bellevue, Tacoma, and Everett.

In more outlying areas like Monroe, Bellingham, Bremerton, Centralia, and Mt. Vernon, May 1 is a good bet. For the usual coldest spots like Olympia, Shelton, and Arlington, they will be garden-ready just a week later. These differences reflect the local climates throughout the region.

Safest time to start gardening

For most, it is around May 1 that seasonal plants can be safely planted in the ground. Just monitor the weather forecast as the end of April approaches. In addition, keep in mind that with longer springtime days, soil temperatures will gradually warm, which will help with root growth.

This end-of-frost-season guidance works for much of Western Washington. Just keep an eye on the upcoming weather forecast before planting or moving plants outside.

The recent warmer, sunny spring weather offered a real temptation to plant seasonals in the yard. Keep any recently purchased seasonals indoors for now. Just hang in there a bit longer before the threat of frost is minimal.

Best wishes for a brilliant garden this year!

Ted Buehner is the KIRO Newsradio meteorologist. Follow him on X and Bluesky. Read more of his stories here.