Packing and clothing: Mexico City in September has mild days and cooler nights due to altitude; pack layers, a light rain jacket for afternoon showers, and comfortable walking shoes for exploring historic districts like Centro Histórico, Roma, and Condesa. Health and altitude: Mexico City sits at over 2,200 meters (7,200 ft); drink water, avoid heavy exertion on arrival, and be mindful if you have respiratory conditions. Booking and logistics: Use midweek flights for lower fares and less crowded terminals at Los Angeles International Airport (LAX). During Sept 15–16, expect higher lodging and transfer demand in Mexico City — book transfers and hotels early. Safety and transport: Use authorized taxis or app-based rideshares at Mexico City International Airport (MEX) and confirm pick-up locations; keep a hotel card in Spanish handy for drivers. CTAs: Sign up for fare alerts, book airport transfers in advance, and check airline baggage policies before packing for your September LAX to MEX trip.