Is junior year really the most important year?

Many say that junior year is the most important year and is the one that colleges look at the most and base their decisions on. Is this true? I assume that they look at all years to make a decision. So if I had okay gpa’s fresh and soph year but had some incredible gpa junior year, would they look at my junior year gpa to base their decision?
Thank you!

Depends how ok and how incredible and what else you did and why it was just ok

Had a friend’s kid played competitive sports as a potential nationally ranked recruit. For personal reasons (which he wrote about in his essays and related to his future ambitions) and injury reasons he quit the sport and decided to concentrate on his academics at the end of sophomore year. He had gotten 2 Bs in his first two years and straight A+ junior and senior year taking all APs in a top school district. He got into a HYP. He had an interesting prospective major and good ECs in an area the college was looking for people but nothing earth shattering.

Holistic admissions means colleges consider all grades. However, Junior year is important because, A. They receive the entire transcript, not none or one semester as with Senior year grades. B. For some students, it is their most intensive year/first year with AP classes, allowing for a good barometer, C. It allows for no more “adjustment period” excuses.

When I’ve heard/read the phrase “junior year is the most important” I have taken it to mean from the standpoint of the applicant more than the admissions committee. There’s just a lot to get done in junior year if you are trying to position yourself for highly selective colleges. Junior year is when you take the PSAT in the Fall and that determines if you qualify for National Merit status and possible NM scholarships. Ideally you want to complete your SAT/SAT2/ACT testing by the end of junior year. The AP classes you have taken through junior year are important because the grades will be on your transcript and any good AP scores can be self reported. Senior year AP classes show course rigor but are still in process when you apply, Your junior year teachers are most likely to be the ones writing your LOR’s.And if you want to apply somewhere ED/EA, it’s especially important to be “ready” in the Fall of senior year, and not to need extra time to bring up the GPA or do additional testing.

Okay, thank you everyone for your help!