To be clear, year-long classes typically get a fall semester grade, a spring semester grade, and a final grade that combines the semesters. It’s the final grade that goes toward the gpa.

Whatever the final grade is at the end of the full length of the class - semester grade for semester classes, end of year grade for year-long classes. That end of year grade already combines the two semester grades in whatever way the school has set for their calculations.

It's generally final grades only for year long courses.

Thank you. It must be our handbook too but I didn’t see it

The information should be found in the student/parent handbook. For our Arlington Diocese High Schools stundent this is how the final grade is calculated:
FULL YEAR COURSES
Eight grades are used to calculate final grades: first quarter, second quarter, first semester exam,
first semester, third quarter, fourth quarter, second semester exam, and second semester. To
calculate first and second SEMESTER grades: numerical average of two quarter grades (each
count 2/5) and exam grade (counts 1/5). The numerical average is then converted to a letter
grade. To calculate the FINAL grade: Numerical average of first semester and second semester
grades. This average is converted to a letter grade.

Child is a Freshman at an Arlington Diocese high school. Obviously for semester classes, that grade is their final grade.

But for year long classes, their final grade would be the average of the two semesters, and is that what is averaged for the final GPA?

I don’t even know who to ask this question at the school.