Word is there's a big storm headed our way starting tonight through tomorrow. JetBlue has already put out a notice that it will waive change fees and fare differences to let travelers booked for travel to, from, or through New York's metro airports or Logan on Wednesday to rebook their flights because of the weather.
Most frequent fliers know that most airlines have such bad-weather change policies; many leisure travelers do not.
Typically this is the way it works: When weather bad enough to force flight cancellations either is looming or has arrived, airlines either will put out a press release or post a message on their websites announcing that the waivers are in effect. There does seem to be differences in how long the carriers will give you to rebook flights. Many require that you rebook within a few days of your original flight. Others will give you the option of booking months later.
If you find yourself facing weather that will likely force flight cancellations, you'll need to check with your airline for the specifics. But be aware that the waiver option is a regular part of doing business for most airlines.