Would need a closer pic of the problem in clear light. From what I can see the top leaves look green with the lower ones yellowing before the naturally die off. You can either cut them off or leave them to grey and protect the trunk.

Thanks for your comment. I uploaded another picture of the green fronds turning yellow. We just moved into this house and have no idea of this is normal

Tpfitzinger:

I'm the editor for Palm Goypedia. Did your Washingtonia robusta palms experience very cold temps this past winter? I know parts of Texas can get very cold in winter. This could be cold damage. Mexican fan palms grow so quickly in hot climates like Texas that you should be able to cut all the old damaged fronds off without any problems.

If your palms are trimmed back, by the end of summer you shouldn't be able to see any signs of the damaged or dead fronds. Like here in Southern California, Mexican fan palms can grow a few dozen fronds from: spring - fall.

A little fertilizer and water will push the fronds out even faster.

I hope this helps!