Colleges' GPA Evaluation

Do colleges look at your whole average high school GPA or each individual year GPA?
What if I had a GPA of 3.8 in freshman year. Unweighted GPA of 3.2 in sophomore and junior year. But I still manage to get a 3.5 GPA as whole average high school GPA, is it still okay?

Schools prefer to see an upward trend in GPA.

@happy1 what if I had an UW 3.2 in junior and then got a UW 3.8 back in senior year?

Schools will only see your first semester grades from your senior year.