Originally Posted by AlwaysAisle

I will not put such pretty picture about US airlines. It is true that when weather condition is developing, such as hurricanes and storms, airlines in the U.S. will issue weather advisory and regardless of a flight is cancelled or not if your flight is on a date mentioned on an advisory and travel through an airport which is mentioned on an advisory then airline will allow you to change your flights without penalty. However, those cases airlines will rebook you on their own flights only, airlines will not rebook you on another airlines with different routing.