Mexico's climate is set by elevation rather than latitude. That single fact explains why a tropical country has cities where you need a jumper in the evening, and it determines where a month works.
The altitude map
| City | Altitude | Climate |
|---|---|---|
| Mexico City | 2,240 m | Mild days, cold nights |
| San Cristóbal | 2,200 m | Cool, misty, needs heating |
| Oaxaca | 1,550 m | Warm days, comfortable nights |
| Guanajuato | 2,000 m | Temperate year round |
| Mérida | 10 m | Hot and humid year round |
| Puerto Escondido | Sea level | Tropical |
Highland accommodation frequently has no heating, which surprises people in San Cristóbal and Mexico City in January. Ask before booking a winter month.
The cities worth a month
Oaxaca — the strongest case. Markets, mezcal, mole, craft villages within an hour, Monte Albán above the valley, and a walkable colonial centre. Warm without being hot.
Mérida — the Yucatán capital, colonial, safe, with cenotes and Maya sites nearby. Hot and humid, which is the trade-off.
Mexico City — enormous, with a neighbourhood for every temperament. Roma and Condesa are the established ones and have become expensive; Coyoacán, Escandón and San Rafael are cheaper.
San Cristóbal de las Casas — highland Chiapas, indigenous markets, cheap, and cold at night.
Guanajuato and Querétaro — central highland colonial cities, both with student populations.
Puerto Escondido — Pacific coast, surf, and a growing long-stay community.
The entry length
Tourist entry has historically been granted for up to 180 days.
Immigration officers have discretion and shorter periods are now commonly issued at both land and air borders.
The length written on your entry record is what governs. Check it on arrival rather than assuming, since planning a five-month stay on a 30-day entry is a serious problem.
What a month costs
| Item | Oaxaca / Mérida | Mexico City |
|---|---|---|
| Furnished 1-bed | $400–800 | $700–1,400 |
| Comida corrida lunch | $4–6 | $5–8 |
| Market shopping, month | $150–250 | $200–300 |
| Transport | $20–40 | $25–45 |
Comida corrida — the fixed-price set lunch — is the daily cost lever, at a few dollars for soup, a main and a drink.
Markets are where the produce is, and prices there are a fraction of supermarket ones.
Safety, practically
Varies enormously by state rather than nationally, and the difference between states is larger than the difference between many countries.
Consult your government's state-by-state advisory rather than treating Mexico as a single risk level.
The cities listed above are in states generally regarded as lower risk, and normal urban precautions apply — avoid displaying valuables, use ride-hailing at night, and take local advice on specific neighbourhoods.
Practical
Water — drink bottled or filtered, and most apartments have a garrafón delivery arrangement.
Rentals are found on short-let platforms and increasingly through local Facebook groups, which are cheaper.
Spanish matters more here than in much of Europe — English is less widely spoken outside the resort corridor, which is also why the language improves faster.
Day of the Dead in Oaxaca fills accommodation months ahead.