Are they potted? I've seen and had King palms look like that in ground..the palm even became a bit wobbly. I think they came near to being killed by gophers or some burrower...The fronds didnt look so good and were smaller then the last set of healthy fronds. Well,cats might have taken care of the gophers,and I made sure to water extra and also fertilize with a dedicate palm fertilizer. They recovered.
Now,all I can say is-maybe your potted palms have a root problem..it might be your potting soil is too peaty,going too wet,then too dry. They need fast drainage. Also,if your's arent on any drip..they could be going to dry..you might try putting a large saucer under them for the summer...it will help the roots wick up the water.
Hope that helps..but the problem is with the roots first ...

Im not sure what the problem is, but I have had this problem with my palms before and eventually with lots of water, it corrects itself. I'm not sure what causes it, maybe someone else can give you some more info!
-Alex