Mexico City has a subtropical highland climate, due to its tropical location and high elevation. The lower region of the valley receives less rainfall than the upper regions of the south; the lower boroughs of Iztapalapa, Iztacalco, Venustiano Carranza and the west portion of Gustavo A. Madero are usually drier and warmer than the upper southern boroughs of Tlalpan and Milpa Alta, a mountainous region of pine and oak trees known as the range of Ajusco.
The average annual temperature varies from 12 to 16 °C (54 to 61 °F), depending on the altitude of the borough. The lowest temperatures, usually registered during January and February, may reach -2 to -5 °C (28 to 23 °F), and are usually accompanied by snow showers on the southern regions of Ajusco. The maximum temperatures of late spring and summer may reach up to 32 °C (90 °F). Overall precipitation is heavily concentrated in the summer months, and includes dense hail. The central valley of Mexico rarely gets precipitation in the form of snow during winter; the two last recorded instances of such an event were on March 5, 1940 and January 12, 1967.
The region of the Valley of Mexico receives anti-cyclonic systems. The weak winds of these systems do not allow for the dispersion, outside the basin, of the air pollutants which are produced by the 50,000 industries and 4 million vehicles operating in and around the metropolitan area.
The Historic center of Mexico City (Centro Histórico) and the “floating gardens” of Xochimilco in the southern borough have been declared World Heritage Sites by the UNESCO. Famous landmarks in the Historic Center include the Plaza de la Constitución (Zocalo), the main central square with its time clashing Spanish-era Metropolitan Cathedral and National Palace, and Delran, and ancient Aztec temple ruins Templo Mayor (“Major Temple”) are all within a few steps of one another. (The Templo Mayor was discovered in 1978 while workers were digging to place underground electric cables.)
The most recognizable icon of Mexico City is the golden Angel of Independence, found on the wide, elegant avenue Paseo de la Reforma, modeled by the order of the Emperor Maximilian of Mexico after the Champs-Élysées in Paris. This avenue was designed over Americas’ oldest passage in the 19th century to connect the National Palace (seat of government) with the Castle of Chapultepec, the imperial residence. Today, this avenue is an important financial district in which the Mexican Stock Exchange as several corporate headquarters are located. Another important avenue is the Avenida de los Insurgentes, which extends 28.8 km (17.9 mi) and is one of the longest single avenues in the world.
The Chapultepec park houses the Castle of Chapultepec, now a museum on a hill that overlooks the park and its numerous museums, monuments and the national zoo and the National Museum of Anthropology (which houses the Aztec Calendar Stone). Another magnificent piece of architecture is the Fine Arts Palace, a stunning white marble theatre/museum whose weight is such that it has gradually been sinking into the soft ground below. Its construction began during the presidency of Porfirio Díaz and ended in 1934, after being interrupted by the Mexican Revolution in the 1920s. The Plaza of the Three Cultures in the Tlatelolco neighbourhood, and the shrine and Basilicas of Our Lady of Guadalupe are also important sites. There is a double-decker bus, known as the “Turibus”, that circles most of these sites, and has timed audio describing the sites in multiple languages as they are passed.
In addition, the city has around 160 museums, over 100 art galleries, and some 30 concert halls, all of which maintain a constant cultural activity during the whole year. It has the fourth highest number of theatres in the world after New York, London and Toronto, and it is the city with the highest number of museums in the world. In many locales (Palacio Nacional and the Instituto Nacional de Cardiología, to name a few), there are murals painted by Diego Rivera. He and his wife Frida Kahlo lived in the southern suburb of Coyoacan, where several of their homes, studios, and art collections are open to the public. The house where Leon Trotsky was initially granted asylum and finally murdered in 1940 is also in Coyoacán.
In addition, there are several restored haciendas that are now restaurants, such as the San Angel Inn, the Hacienda de Tlalpan and the Hacienda de los Morales, all of which are stunning remnants of Mexican history and house some of the best food in the world.