Almost all classes at my kids’ large, public CA high school are one year long. On the official transcript, two grades show for each year-long class (one for each semester; A+, A, A-). The rare half-year classes only have one grade on the transcript.
So far, most schools my son has applied for ask applicants to list for each semester grade, as does the Common App.
I’m glad someone asked this question, because I was kind of embarrassed that I used to think, and even told my older son during freshman year at one point, that only the last grade of the year mattered (that was totally wrong, obviously).