Not all all compared to the Japanese.
Considering Pearl Harbor was a Military installation, of course it was prepared to an extent, there were people that had the job of waiting for an attack, that would then man the AA guns and other defenses.
However they were not as prepared as they could have been if they knew something was coming, heck, they weren't even in the war at this point.
The Japanese had months, maybe years (I forgot) to plan this attack. It was well coordinated and obviously took a big tole on the Americans.
So no, the Americans were not that well prepared for what had come.
Hope this helps!
