https://www2.montgomeryschoolsmd.org/contentassets/80ee165412504289898564aff64ac79a/physical-evaluation-for-athletics-sr-8-rev-0619.pdf

Physical Forms are good for 13 months.  Example:  if you got a physical on August 2nd 2023, it would expire September 2nd, 2024

It is recommended to get your physicals completed in the summer so they cover all 3 seasons.