RE: https://mstdn.social/@mattmay/116988858841146726
Very important! A group of people I know tested out the time for mail to be delivered in Washington state a couple of months ago, and while it's often quite fast there are times where even going between adjacent zip codes can take up to ten days.
For the August 4 primary in Washington, at this point it's better to drop off your ballots at a drop box -- King County Elections has a map of all the dropboxes in Washington state. If you are going to mail your ballot though, please do it ASAP!