Hii!
The eligibility criteria to join meterology department of IAF states that the Candidate must have passed post graduation degree with minimum 50% marks in either one of the subjects - statistics, geography, computer Application, Mathematics, EVS, applied Physics, oceanography, Agricultural meterology, meterology, environmental biology, geophysics, ecology and environment, or any other science stream Subject.
They must have done graduation with atleast 50% marks with maths and physics as compulsory subjects and having secured atleast 55% marks in each.
Hope this helps.
Good luck!