Okay, so I now have it clear about the last day(s) of school for SPS students. It has been a challenge for all involved, especially Communications, as (1) the info for them changed over two days and (2) the website coordinators have not kept up and there is differing information right on the SPS homepage.
Here's the correct info right off the webpage from Communications:
Tuesday, June 21 - Last Day of School for Elementary and K-8 Students with a one-hour early dismissal
Thursday, June 23 - Last Day of School for Middle and High School Students with a one-hour early dismissal
Tuesday, June 21st, all elementary, K-8 and middle schools will have a one-hour early dismissal (except Aki Kurose which will stay on its regular schedule). Even though the middle schools are releasing one hour early that day, it is NOT their last day of school.
High schools will release on a normal schedule on Tuesday EXCEPT for Chief Sealth and West Seattle which will also release one hour early.
I have never seen such weirdness for the last day of school.