when will my grandaddy be ready??

hey i have a few questions. i put my grandaddy purple oudoor in late may i was wondering when will it be ready to harvest. its aleardy in flowering stage will it be ready by the end of september or october?? i live in northern california the wheater is been in the high 70 low 80's will it turn purple what are my chances?? and i also have three other plants i dont know what strain they are i got them form seeds but one is truning purple and its growing like a sativa strain. i will post some pics soon please help.

theyll probably be done by late october...... usually buds only turn color with the cold so the colder the purplier

damn lat october i cant wait it should be a nice grow for my firsdt time

just cuz it purp dont mean it will turn purp.