Engrishprf:
carriers are not required under any US regulation to provide compensation for a cancelled flight, regardless of the reason. As far as weather, while the weather at your departing and arriving cities might be clear, they may have been weather issues along the flight plan, at the city in which the aircraft or flight crew is departing on, ect. When a carrier cancels a flight, it not only impacts that flight, but the aircraft and crews are not in position for the next flights.
In regards to not getting in touch with anyone at AA, pelase send a complaint to
http://airconsumer.ost.dot.gov/problems.htm and we can try to get your a response from American.