Yea, things in aviation do take long to change.
I just heard from someone that they ask that question as a trick question, and that like we all read in the AIM, it all depends on your altitude.
Heres another quick one. A TAF comes out 4 times a day, every 6 hours, and is valid for 24 hours. A METAR comes out every-hour, unless there is some sort of special weather or a significant change in weather, then it comes out anytime-as a SPECI(which has its own criteria). How long is it valid for, a SPECI is valid for up to 2 hours. In that case I assume a METAR is valid only for that 1 hour till a new one comes out, yes? That only seems to make sense.
