When should I prune roses in Seattle?
In the Greater Seattle area, the general rule of thumb is to prune your roses from ‘later’ February (February 22) on through mid-March.

There is an excellent indicator to help. Have a look around your neighborhood or in your own yard. Are the Forsythias in bloom? If so, then it’s the correct time to prune your Seattle roses.
Forsythia is sensitive to temperature and to light. Hence it will not bloom until the optimal time. And that’s the optimal time to be pruning roses in Seattle.