Every year tens of thousands of juniors take the Preliminary SAT/National Merit Scholarship Qualifying Test (PSAT/NMSQT) in October in the hopes of being in the top 1% to earn the National Merit Semifinalist standing. But the high scorers don't know whether they made the top 1% cutoff until September of senior year.
While no one can really predict the numbers, I've followed CompassPrep for several years now and their estimates are usually fairly close to the actual numbers released every August.
Students can use the National Merit Selection Index on their score report and the information in this article to assess where they stand.
https://www.compassprep.com/national-merit-semifinalist-cutoffs/?fbclid=IwAR3PEtSYNU2FstX3vyXKkfQW0QkgavlPs2plTQewaMupWL0Q13tB5wGdz4A