From the WSDOT Press Release Center:

Spring is here but the potential of some late season snow means the deadline to remove studded tires in Washington has been extended for two weeks.
The removal deadline is now by the end of the day, Sunday, April 15.

State law allows the Washington State Department of Transportation to extend the deadline into April if current or predicted conditions could make
for difficult travel. The decision to extend is made in consultation with meteorologists and maintenance supervisors. The deadline was last extended
in 2012.

This year’s decision was based on long-range forecasts that show the potential for significant weather, including snow that could affect cross-state
travel into April.

With the extension, all studded tires need to be removed no later than the end of the day (11:59 p.m.) Sunday, April 15. Starting Monday, April 16,
drivers with studded tires on their vehicles face a $136 traffic infraction. Removal services can be crowded as the deadline approaches, so please
plan accordingly.

Studded tires damage pavement each year – costing an estimated $29 million annually in additional wear and tear on state roads alone. Long-term, WSDOT
continues to urge drivers to investigate alternatives such as studless winter tires, which are not subject to removal deadlines.

Washington and Oregon generally share the same studded tire removal deadline and the Oregon Department of Transportation also is extending its removal
deadline to April 15. Other states may have later tire removal dates, but the Washington law applies to all vehicles in the state, even those visiting
from elsewhere. There are no personal exemptions or waivers beyond the extension date.