Lol if the weather going coolar whats need of A/C
check ur rediator
also do a test start engine open the rediator cup and accelerate engine and then see at stop if u getting boiling water then there are some thing wrong with head cuz head cause problem in temprature range
See your Rediator and ur condensor cooling fans turn on when u switch Air con On they should be countinus on on ac
check ur condensor and clean it
Also engine belt that rotate your compressor
check ur needle is well
Dont let the needle crossing mid sign of ur temp range
and last but more important check ur cluthch plate and pressure plate