Choosing your Mexican coast
Mexico is not one destination and the choice of coast matters more than the choice of resort. The Caribbean side — Cancun and the Riviera Maya — has the postcard water, the largest concentration of resorts, and the cenotes and Mayan sites. The Pacific side, meaning Puerto Vallarta and Los Cabos, has dramatic scenery, better whale watching, and a different feel entirely. Both fly direct from Calgary for much of the year.
The single most useful thing a Calgary traveller can know about the Caribbean coast is sargassum. Between roughly April and August, seaweed can arrive on Cancun and Riviera Maya beaches in volumes that resorts cannot fully clear, and it is the most common cause of a disappointing week on that coast. It is seasonal, it varies year to year, and it does not affect the Pacific side at all.
That gives you a straightforward planning rule. For a winter trip between December and March, the Caribbean coast is at its best and is the obvious choice. For late spring and summer, Puerto Vallarta and Los Cabos avoid the sargassum question entirely. We would rather tell you this before you book than have you discover it from your balcony.