Since you're heading to a tropical climate, I would recommend you specifically get a line rated for fishing the tropics. I recently went to the Gulf Coast of Florida, and I switched my lines to tropical fly lines. They worked perfectly. I used a Rio floating line on one reel, and an Outbound Short intermediate on the other. The Outbound cast better than the floating line, but a weight forward floating tropical line would probably be the best choice for what you're going after.
Cold water fly lines are designed to stay limp and cast well in cold conditions. In the tropics, they become too soft and lose their performance. A tropical line is made of stiffer material, which will balance out nicely in the tropical heat.
I learned this recently from others here on the forum. My trip to Florida was my first, and I'm glad I asked folks about proper lines before I went. It made a huge difference.
As far as the California coast, I wouldn't use a tropical line here. Since the current comes down from Alaska, our water stays pretty much in the 60's most of the year. A Streamer Express from Scientific Anglers is great for surf fishing around here.
Have fun in Cancun, and post pictures of your fish when you get back.