valleys of Mexico and Puebla. It rises over two different ecological zones: alpine meadows and subalpine forests. The rainy season starts in May and lasts until October. The highest annual temperature occurs in April, the onset of the rainy season, and the lowest in December–January. Some 500 years ago weather conditions were slightly more severe, but the best time to climb the mountain was practically the same as today: October through December, and February until the beginning of May. The date of the feast of Huey Tozotli celebrated atop Mount Tlaloc coincided with a period of the highest annual temperature, shortly before dangerous thunderstorms might block access to the summit. Archaeological evidence The first detailed account of Mount Tlaloc by Jim Rickards in 1929 was followed by visits or descriptions by other scholars. In 1953 Wicke and Horcasitas carried out preliminary archaeological investigations at the site; their conclusions were repeated by Parsons in 1971. Archaeo-astronomical research began in 1984, some of which remains unpublished. In 1989 excavation was undertaken at the site by Solis and Townsend. The current damage that is present at the top of Mount Tlaloc is thought to be likely of human destruction, rather than natural forces. There also appears to have been a construction of a modern shrine that was built in the 1970s, which suggests that there was a recent/present attempt to conduct rituals on the mountain top. See also Aktzin Cocijo Chaac Mount Tlaloc Tlaloque Notes References External links Tlaloc image at the Federation for the Advancement of Mesoamerican Studies Aztec gods Sky and weather gods Thunder gods Fertility gods Rain deities Earth gods Water gods