Do colleges look at your transcript average from the end of junior year or the middle of senior year?

When I apply to colleges and they look at my transcript cumulative average, do they look at the average from the end of my junior year, or the one I send during the middle of my senior year? If my average drops because of one teacher that grades low, will they see it?Do colleges look at your transcript average from the end of junior year or the middle of senior year?
They look at your grades up to the first term of your senior year, usually. Unless you apply early decision, then it is up until the end of your junior year.Do colleges look at your transcript average from the end of junior year or the middle of senior year?
They look at all your grades. 9-12th grade.