How long will smoking weed stay in my system ?

Long enough: Long enough to be detected by a drug screen.

Days to weeks: Thc, the active component of weed, is fat soluble, which means that it finds its way into fat tissue and is released gradually over time. Intoxication depends on the blood level of thc, so the high is unlikely to last more than hours at a time, but the thc is excreted from the body over a much longer period of time.

It depends: Depending on how frequently you use marijuana, it can be detected in urine for 5 to 90 days. It's stored in fat, and will stay there even if you're of normal weight. It will remain in your hair follicles for about 90 days also.