https://www2.montgomeryschoolsmd.org/siteassets/district/departments/athletics/health/sr-8-physical-form-with-covid-supplement3.pdf

Physical Forms are good for one calendar year.  Example:  if you got a physical on August 2nd 2021, it would expire August 2nd, 20222

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