Mexico City: what should you know about altitude, season and getting around?

Question, scoped First visit to Mexico City, five days. What should you plan for? As of October 2026. The answer - Altitude: the city is at about 2,240 metres (7,350 feet). Many visitors feel breathless or get headaches for the first day or two. Drink water, go easy on alcohol, and do not plan the hardest day first. - Season: the dry season runs roughly November to April. June to September is the rainy season, with heavy afternoon storms; plan museums for the afternoon. Día de Muertos (November 1 and 2) is a major event, and the large parade in the centre has been held since 2016. - Water: drink bottled or filtered water. Restaurants generally use purified water and ice. - Earthquakes: the city has a public seismic early-warning system (SASMEX), with loudspeaker alerts that can sound before shaking arrives. If you hear the alert, follow local people to the designated safe area. - Getting around: the Metro is cheap and extensive but very crowded at rush hour; some trains have women-and-children-only carriages. Ride-hail apps are widely used and are a common way to get around at night. - Entry: US citizens need a valid passport. Mexico has moved its tourist entry record (FMM) to a digital process at major airports; keep the record of your permitted stay. Sourced US State Department Mexico page (https://travel.state.gov) and Mexico City government information. What would change this answer Travel advisories, which the State Department sets state by state; read the one for Mexico City and for any side trips. Weather planning: https://weather.soapbox.community