Here is a link to our website with the regulations regarding the use of electronic callers in the State of Washington. We have regulations from every state available on our website. In a nutshell, adnahoundsman is correct, except that elk, waterfowl, and migratory game birds are not allowed to be called with the use of an electronic caller or decoy.
You're good. Night hunting ended yesterday, near as conservative interpretation of the law can figure. But Coyotes are year round. Read the pamphlets carefully, WA laws are a convoluted mess.