Here is a picture of how good it looked back in September.

Wow, it looked really beautiful back in October. Considering that the damage happened over the winter and the fact that my outdoor palms are showing very similar damage to yours right now, I want to say it's cold damage. Temperatures in the upper 30s shouldn't do damage to your Fiji fan palm, but maybe it's possible that your yard is in a cold microclimate or maybe the individual palm is just a bit more sensitive to the cold than the species as a whole. Livistonias are supposed not show frond damage until temperatures reach the mid 20s but I have 2 livistonas that show damage whenever temperatures go much below freezing.

When did the damage start to show and is it getting progressively worse or has it stopped? If the damage over the span of a few days or a week or 2, it's a good sign it might be cold damage.

I hope it recovers. If it is cold damage it should have no problem recovering in the spring!

Good luck!
-Alex

Fiji Island is not easy outside its native range--they are just too tropical. I tried a few times without success.

This is the only Pritchardia I grow, and it's easy.

Here is a link that might be useful: Pritchardia hildibrantii

The problem has been occurring for just about 2 weeks.
Hopefully it's only from some cold damage. We probably
didn't get the frost this year, but there were more days
than normal where the highs were in the high 50's and the
lower 60's. Thanks

Pritchardia pacifica isn't a palm for zone 9b/10a, it doesn't need frost to kill it. Cold rain in winter wouldn't do it any good. As njoasis said, there are other Pritchardias that are far more adapted to cold.

They are definitely very tropical. With protection from the cold and winter rains you can probably get away with growing them but they are sensitive to the cold. Yours will easily come back this year with the long growing season that you have, but it will probably die during a winter with a freeze.

Good luck!
-Alex

the fact your palm is still alive this month is in itself surprising, as almost no one in any part of California can keep one of those alive through a single winter (are some exceptions, but rare and rarely look good and never thrive... and almost all die after 2-3 years). Are over a dozen Pritchardia that are better choices for California.. in fact, All Pritchardia EXCEPT that, and two other species, do OK here.

I live in Costa Rica (no excuses of cold weather here), and I am having the same problem