When does applying regular decision in the spring vs. fall matter?

I'm trying to figure out if there's any advantage to applying regular decision in the spring compared to the fall. Does it impact my chances of admission or financial aid opportunities?

It seems like there might be a bit of confusion here. When talking about applying to colleges, the fall and spring of your senior year reference different aspects of the process.

In the fall of your senior year, you are actually submitting your applications (Regular Decision deadlines typically fall between January 1 - February 1), and in the spring of your senior year, you're receiving decisions and choosing where to attend.

Applying early (in the fall) mainly advantages you by ensuring that your application is in ahead of the crowd. For some schools, rolling admissions also mean that you could receive your decision ahead of the official Regular Decision release date.

To my knowledge, there isn't really a common "spring application" period that happens in the second semester of a student's senior year. A few colleges offer a Spring Admission cycle where you would start at the college in the Spring semester instead of the Fall semester, if this is what you were referencing. However, keep in mind this isn't common and you'll need to check if your specific colleges of interest offer this.

As for financial aid and scholarships, the quicker you complete your application materials (including the FAFSA), the better. Some schools grant scholarships and financial aid on a first-come, first-serve basis, so there could be a financial advantage to completing all necessary materials in the fall.

Therefore, waiting until the spring to apply via Regular Decision (when deadlines have usually passed) would typically not be advantageous, as you may miss out on potential admission and financial aid opportunities. Going forth with applying in the fall, as per the typical timeline, would be the standard advice.