met
It is a tough one and does take time to learn, as mentioned the Oxford cd really explaines well, it is also one of the few subjects you actually use when flying. Having knowlege of weather can one day save your life, when weather radar's go on the blink, which they do you need to know what to do.
Save yourself the hassel of learning thick books and difficult explainations, all you need is the CD and you will be fine.