We are looking to go someplace warm, but I'm hearing wear layers, bring a jacket and sweatshirts, cloudy days, no pool weather...ackkk!??
Anyone have relaiable info?
I don't know who is playing games with you by feeding you that nonsense. The entire Mexican Riviera, including Cabo San Lucas, is in the tropics. In several cruises to the Mexican Riviera, I have yet to encounter anything other than lots of sunshine with daytime temperatures in the 80's to low 90's and ocean temperatures that are great for swimming.
Realisticaly, the first and last days at sea traniting between either San Diego or Los Angeles and Cabo San Lucas may be a bit cooler. On those two days, you might want a sweater, a sweatshirt, or a light jacket of you go out on deck. I also recommend bringing a waterproof jacket in case you encounter a shower during a port of call, but it's a region where rain is pretty rare.