Tlaloc (Classical Nahuatl: Tlāloc [ˈtɬaːlok]) is a member of the pantheon of gods in Aztec religion. As supreme god of the rain, Tlaloc is also a god of earthly fertility and of water. He was widely worshipped as a beneficent giver of life and sustenance. However, he was also feared for his ability to send hail, thunder, and lightning, and for being the lord of the powerful element of water. Tlaloc is also associated with caves, springs, and mountains, most specifically the sacred mountain in which he was believed to reside. His animal forms include herons and water-dwelling creatures such as amphibians, snails, and possibly sea creatures, particularly shellfish. The Mexican marigold, Tagetes lucida, known to the Aztecs as yauhtli, was another important symbol of the god, and was burned as a ritual incense in native religious ceremonies.
The cult of Tlaloc is one of the oldest and most universal in ancient Mexico. Although the name Tlaloc is specifically Aztec, worship of a storm god like Tlaloc, associated with mountaintop shrines and with life-giving rain, is as at least as old as Teotihuacan and likely was adopted from the Maya god Chaac or vice versa, or perhaps he was ultimately derived from an earlier Olmec precursor. An underground Tlaloc shrine has been found at Teotihuacan.
In Aztec iconography, Tlaloc is usually depicted with goggle eyes and fangs. He is most often coupled with lightning, maize, and water in visual representations and artwork. Offerings dedicated to Tlaloc in Tenochtitlan were known to include several jaguar skulls and even a complete jaguar skeleton. Jaguars were considered the ultimate sacrificial animal due to their value.
Tlaloc's impersonators often wore the distinctive mask and heron-feather headdress, usually carrying a cornstalk or a symbolic lightning bolt wand; another symbol was a ritual water jar. Along with this, Tlaloc is manifested in the form of boulders at shrine-sites, and in the Valley of Mexico the primary shrine of this deity was located atop Mount Tlaloc.
In Coatlinchan, a colossal statue weighing 168 tons was found that was thought to represent Tlaloc. However, one scholar believes that the statue may not have been Tlaloc at all but his sister or some other female deity. This statue was relocated to the National Museum of Anthropology in Mexico City in 1964.
While pre-Hispanic cultures are thought to have become extinct once the Spanish had completed the colonization of Mexico, aspects of pre-Hispanic cultures continue to influence Mexican culture. Accordingly, Tlaloc has continued to be represented in Mexican culture even after the Spanish were thought to have completed evangelizing in Mexico. In fact, even as the Spanish were begging to proselytize in Mexico, religious syncretism was occurring. Analyses of evangelization plays put on by the Spanish, in order to convert the indigenous peoples to Christianity, suggests that the Spanish might have unknowingly created connections between Christianity and indigenous religious figures, such as Tlaloc. Indigenous Mexicans viewing these plays might have made connections between the sacrifice Abraham was willing to make of Isaac, to the sacrifices that were made to Tlaloc and other deities. These connections may have allowed indigenous peoples to retain ideas about sacrifice even as they were being forcibly converted to Christianity. Early syncretism between indigenous religions and Christianity, also included more direct connections to Tlaloc. Some churches built during the sixteenth century, such as the Santiago Tlatelolco church had stones depicting Tlaloc within the interior of the church. Even as the Roman Catholic Church sought to eradicate indigenous religious traditions, depiction of Tlaloc still remained within worship spaces, suggesting that Tlaloc would still have been worshipped after Spanish colonization. It is clear that Tlaloc would have continued to have played a role in Mexican cultures immediately after colonization.
Despite the fact that it has been nearly half a millennium since the conquest of Mexico, Tlaloc still plays a role in shaping Mexican culture. At Coatlinchan, a giant statue of Tlaloc continues to play a key role in shaping local culture, even after the statue was relocated to Mexico City. In Coatlinchan, people still celebrate the statue of Tlaloc, so much so that some local residents still seek to worship him, while the local municipality has also erected a reproduction of the original statue. Many residents of Coatlinchan, relate to the statue of Tlaloc in the way that they might associate themselves with a patron saint, linking their identity as a resident of the town with the image of Tlaloc. While Tlaloc plays an especially important role in the lives of the people of Coatlinchan, the god also plays an important role in shaping the Mexican identity. Images of Tlaloc are found throughout Mexico from Tijuana to the Yucatán, and images of the statue of Tlaloc found at Coatlinchan are deployed as a symbol of the Mexican nation. Tlaloc and other pre-Hispanic features are critical to creating a common Mexican identity that unites people throughout Mexico. Accordingly, people throughout Mexico, and especially in Coatlinchan, refer to Tlaloc in very anthropomorphized ways, referring to Tlaloc as a person. Furthermore, people continue to observe superstitions about Tlaloc. Despite centuries of colonial erasure, Tlaloc continues to be represented in Mexican culture.
Evidence suggests that Tlaloc was represented in many other Mesoamerican cultures and religions. Tlaloc is thought to be one of the most commonly worshipped deities at Teotihuacan and it is specifically here, in Teotihuacan, that representations of Tlaloc often show him having jaguar teeth and features. This differs from the Maya version of Tlaloc, as the Maya representation depicts no specific relation to jaguars. The inhabitants of Teotihuacan thought of thunder as the rumblings of the jaguar and associated thunder with Tlaloc as well. It is likely that this god was given these associations because he is also known as "the provider" among the Aztecs.
A chacmool excavated from the Mayan site of Chichén Itzá in the Yucatán by Augustus Le Plongeon possesses imagery associated with Tlaloc. This chacmool is similar to others found at the Templo Mayor in Tenochtitlán. The chacmool found at Chichén Itzá appears to have been used for sacrificial purposes, as the chacmool is shaped like a captive who has been bound. Likewise, two of the chacmools that have been found at Templo Mayor make clear reference to Tlaloc. The first chacmool portrays Tlaloc three times. Once on the vessel for collecting the blood and heart of sacrificed victims, once on the underpart of the chacmool with aquatic motifs related to Tlaloc, and the actual figure of the chacmool itself is of Tlaloc as the figure portrays the iconic goggle eyes and large fangs. The other chacmool was found at the Tlaloc half of the double pyramid-temple complex and clearly represents Tlaloc for the same reasons. In addition to the chacmools, human corpses were found in close proximity to the Tlalocan half of Templo Mayor, which were likely war captives.
These archaeological findings could explain why the Maya tended to associate their version of Tlaloc, Chaac, with the bloodiness of war and sacrifice, because they adopted it from the Aztecs, who used Mayan captives for sacrifice to Tlaloc. Furthermore, Tlaloc can be seen in many examples of Mayan war imagery and war-time decoration, such as appearing on “shields, masks, and headdresses of warriors”  This evidence affirms the Mayan triple connection between war-time, sacrifice, and the rain deity as they likely adopted the rain deity from the Aztecs, but blurred the line between sacrifice and captive capture, and religion.
Tlaloc was also associated with the earth, and it is believed this is also a reason why sacrifices may have been made to him. Sacrifices to Tlaloc were not solely a Maya phenomenon, and it is known that the Aztecs also made sacrifices to Tlaloc. Just as the Maya had also worshipped their own version of Tlaloc, so did the Mixtec people of Oaxaca, who were known to worship a rain god that is extremely similar to other manifestations of Tlaloc. The commonalities between the different Mesoamerican cultures; interpretations of Tlaloc belies the common origin of Tlaloc as a rain god from Teotihuacán.
Ever since the identification of Tlaloc as the Rain God who had large fangs and goggled eyes, there seems to be an over-labeling of different religious figures as Tlaloc. This is an issue because too many deities are being oversimplified and branded as Tlaloc or versions of Tlaloc, even with very little evidence or archaeological support. This is likely because of the extensive list of symbols that are related to Tlaloc, whether correctly or unreasonably. “Armillas’ list of elements associated with Tlaloc includes a large proportion of Teotihuacan iconography, including the jaguar, serpent, owl, quetzal, butterfly, bifurcated tongue, water lily, triple-shell symbol, spider” and more. Archaeologist have started to compare different religious icons featured on murals and pottery to the “classic” Tlaloc and Tlaloque characteristics in order to rule out individuals who do not actually represent Tlaloc. 
For instance, some figures found at Tepantitla were named Red Tlalocs as they were colored red and had faint similarities to the actual physical features of Tlaloc. However, these “Red Tlalocs” were disassociated with Tlaloc as the mural they are featured in contains no reference to water, fertility, or growth, and none of the facial features or headdresses are similar enough to those associated with Tlaloc or the Tlaloque, such as the versions of Tlaloc in Codex Borgia. Therefore, some archaeologists threw out the preconceived notion that these entities were related to Tlaloc at all and they are likely to be other lesser known deities that need more research to be correctly named. Due to the increased quantity of pottery that have been found since the 1940s, there is more information to work with and likely a better, more precise differentiation between the gods of Mesoamerica.
In Aztec cosmology, the four corners of the universe are marked by "the four Tlalocs" (Classical Nahuatl: Tlālōquê [tɬaːˈloːkeʔ]) which both hold up the sky and function as the frame for the passing of time. Tlaloc was the patron of the Calendar day Mazātl. In Aztec mythology, Tlaloc was the lord of the third sun which was destroyed by fire.
On page 28 of the Codex Borgia, the Five Tlaloque are pictured watering maize fields. Each Tlaloc is pictured watering the maize with differing types of rains, of which only one was beneficial. The rain that was beneficial to the land was burnished with jade crystals and likely represented the type of rain that would make a bountiful harvest. The other forms of rain were depicted as destroyers of crops, “fiery rain, fungus rain, wind rain, and flint blade rain”. This depiction shows the power that Tlaloc had over the Central American crop supply. Also, the high ratio of damaging rains to beneficial rains likely symbolizes the ratio of the likelihood that crops are destroyed to them being nourished. This would explain why so much effort and resources were put forth by the Central Americans in order to appease the Gods.
Additionally, Tlaloc is thought to be one of the patron deities of the trecena of 1 Quiahuitl (along with Chicomecoatl). Trecenas are the thirteen-day periods into which the 260-day calendar is divided. The first day of each trecena dictates the augury, or omen, and the patron deity or deities associated with the trecena.
In Aztec mythic cosmography, Tlaloc ruled the fourth layer of the upper world, or heavens, which is called Tlalocan ("place of Tlaloc") in several Aztec codices, such as the Vaticanus A and Florentine codices. Described as a place of unending springtime and a paradise of green plants, Tlalocan was the destination in the afterlife for those who died violently from phenomena associated with water, such as by lightning, drowning, and water-borne diseases. These violent deaths also included leprosy, venereal disease, sores, dropsy, scabies, gout, and child sacrifices.
The Nahua believed that Huitzilopochtli could provide them with fair weather for their crops and they placed an image of Tlaloc, who was the rain-god, near him so that if necessary, the war god could compel the rain maker to exert his powers.
Tlaloc was also associated with the world of the dead and with the earth. His name is thought to be derived from the Nahuatl word tlālli "earth", and its meaning has been interpreted as "path beneath the earth," "long cave," or "he who is made of earth." J. Richard Andrews interprets it as "one that lies on the land," identifying Tlaloc as a cloud resting on the mountaintops. Other names of Tlaloc were Tlamacazqui ("Giver") and Xoxouhqui ("Green One"); and (among the contemporary Nahua of Veracruz), Chaneco.
In the Aztec capital Tenochtitlan, one of the two shrines on top of the Great Temple was dedicated to Tlaloc. The high priest who was in charge of the Tlaloc shrine was called "Quetzalcoatl Tlaloc Tlamacazqui." It was the northernmost side of this temple that was dedicated to Tlaloc, the god of rain and agricultural fertility. In this area, a bowl was kept in which sacrificial hearts were placed on certain occasions, as offerings to the rain gods. Although the Great Temple had its northern section dedicated to Tlaloc, the most important site of worship of the rain god was on the peak of Mount Tlaloc, a 4,100 metres (13,500 ft) mountain on the eastern rim of the Valley of Mexico. Here the Aztec ruler would come and conduct important ceremonies annually. Additionally, throughout the year, pilgrims came to the mountain and offered precious stones and figures at the shrine. Many of the offerings found here also related to water and the sea.
The Tlalocan-bound dead were not cremated as was customary, but instead they were buried in the earth with seeds planted in their faces and blue paint covering their foreheads. Their bodies were dressed in paper and accompanied by a digging stick for planting put in their hands.
The second shrine on top of the main pyramid at Tenochtitlan was dedicated to Tlaloc. Both his shrine, and Huitzilopochtli′s next to it, faced west. Sacrifices and rites took place in these temples. The Aztecs believed Tlaloc resided in mountain caves, thus his shrine in Tenochtitlan’s pyramid was called "mountain abode." Many rich offerings were regularly placed before it, especially those linked to water, such as jade, shells, and sand. Mount Tlaloc was situated directly east of the pyramid. It was forty-four miles away, with a long road connecting the two places of worship. On Mount Tlaloc, there was a shrine containing stone images of the mountain itself and other neighboring peaks. The shrine was called Tlalocan, in reference to the paradise. Also, the shrine contained four pitchers containing water. Each pitcher would produce a different fate if used on crops: the first would bring forth a good harvest, the second would cause the harvest to fail and rot, the third would dry the harvest out, and the final one would freeze it. Sacrifices that took place on Mount Tlaloc were thought to favor early rains.
The Atlcahualo festivals was celebrated from the 12th of February until the 3rd of March. Dedicated to the Tlaloque, this veintena involved the sacrifice of children on sacred mountaintops, like Mount Tlaloc. The children were beautifully adorned, dressed in the style of Tlaloc and the Tlaloque. The children to be sacrificed were carried to Mount Tlaloc on litters strewn with flowers and feathers, while also being surrounded by dancers. Once at the shrine, the children's hearts would be pulled out by priests. If, on the way to the shrine, these children cried, their tears were viewed as positive signs of imminent and abundant rains. Every Atlcahualo festival, seven children were sacrificed in and around Lake Texcoco in the Aztec capital. The children were either slaves or the second-born children of noblepeople, or pīpiltin.
The festival of Tozoztontli (24 March – 12 April) similarly involved child sacrifice. During this festival, the children were sacrificed in caves. The flayed skins of sacrificial victims that had been worn by priests for the last twenty days were taken off and placed in these dark, magical caverns.
The winter veintena of Atemoztli (9 December – 28 December) was also dedicated to the Tlaloque. This period preceded an important rainy season, so statues were made out of amaranth dough. Their teeth were pumpkin seeds and their eyes, beans. Once these statues were offered copal, fine scents, and other food items, while they were also prayed to and adorned with finery. Afterwards, their doughy chests were opened, their "hearts" taken out, before their bodies were cut up and eaten. The ornaments with which they had been adorned were taken and burned in peoples’ patios. On the final day of the "veintena," people celebrated and held banquets.
Tlaloc was also worshipped during the Huey Tozotli festival, which was celebrated annually. Evidence from the Codex Borbonicus suggests that Huey Tozotli was a commemoration of Centeotl, the god of maize. While Tlaloc is not normally associated with Huey Tozotli, evidence from the Codex Borbonicus indicates that Tlaloc was worshipped during this festival. Additional evidence from the Book of Gods and Rites suggest rulers from the Aztec Empire and other states would make a pilgrimage to Mount Tlaloc during the Huey Tozotli festival in order to present offerings to Tlaloc. The Book of Gods and Rites also suggests that a child was sacrificed as a part of this pilgrimage as well, although this could simply be the result of colonial sensationalism on the part of the Spanish authors. It is argued that Tlaloc was incorporated into celebrations of Huey Tozotli because of his role as the god of rain. Huey Tozotli was a celebration of the maize harvest, and it would make sense that worshippers might want to celebrate Tlaloc during this festival as his powers of the rain would be critical to having a successful harvest of maize.
Tlaloc was linked to the regenerative capacity of weather, and, as such, he was worshipped at Mount Tlaloc because much of the rain in Central Mexico is formed over range of which Mount Tlaloc is a part. Tlaloc was worshipped on Mount Tlaloc during the Etzalcualiztli festival, in which rulers from across Central Mexico performed rituals to Tlaloc in order to ask for rain, and to celebrate fertility and the change of the seasons. An important part of these pilgrimages to Mount Tlaloc during Etzalcualitztli was the sacrifice of both adults and children to Tlaloc.
Archaeological evidence indicates Tlaloc was worshiped in Mesoamerica before the Aztecs even settled there in the 13th century AD. He was a prominent god in Teotihuacan at least 800 years before the Aztecs. This has led to Meso-American goggle-eyed rain gods being referred to generically as "Tlaloc," although in some cases it is unknown what they were called in these cultures, and in other cases we know that he was called by a different name, e.g., the Mayan version was known as Chaac and the Zapotec deity as Cocijo.
Chalchiuhtlicue, or "she of the jade skirt" in Nahutatl, was the deity connected with the worship of ground water. Therefore, her shrines were by springs, streams, irrigation ditches, or aqueducts, the most important of these shrines being at Pantitlan, in the center of Lake Texcoco. Sometimes described as Tlaloc's sister, Chalchiuhtlicue was impersonated by ritual performers wearing the green skirt that was associated with Chalchiuhtlicue. Like that of Tlaloc, her cult was linked to the earth, fertility and nature's regeneration.
Tlaloc was first married to the goddess of flowers, Xochiquetzal, which literally translates to "Flower Quetzal." Xochiquetzal personifies pleasure, flowers, and young female sexuality. In doing so, she is associated with pregnancies and childbirths and was believed to act as a guardian figure for new mothers. Unlike many other female deities, Xochiquetzal maintains her youthful appearance and is often depicted in opulent attire and gold adornments.
There is a sanctuary found atop Mount Tlaloc, dedicated to the god, Tlaloc; it is thought that the location of this sanctuary in relation to other temples surrounding it may have been a way for the Aztecs to mark the time of year and keep track of important ceremonial dates. Research has shown that different orientations linked to Mount Tlaloc revealed a grouping of dates at the end of April and beginning of May associated with certain astronomical and meteorological events. Archaeological, ethnohistoric, and ethnographic data indicate that these phenomena coincide with the sowing of maize in dry lands associated with agricultural sites. The precinct on the summit of the mountain contains 5 stones which are thought to represent Tlaloc and his four Tlaloque, who are responsible for providing rain for the land. It also features a structure that housed a statue of Tlaloc in addition to idols of many different religious regions, such as the other sacred mountains. 
Mount Tlaloc is the highest peak of the part of the Sierra Nevada called Sierra del Rio Frio that separates the valleys of Mexico and Puebla. It rises over two diffierent 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.
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 .
Contemporary artist Jesse Hernandez has interpreted Tlaloc in his "Urban Aztec" style at several points throughout his career, including hand-painted upon a 16" Qee in 2008, as a painting titled Rain God in 2012, and as a factory-produced Dunny with Kidrobot in 2018.
To him was attributed the rain; for he made it, he caused it to come down, he scattered the rain like seed, and also the hail. He caused to sprout, to blossom, to leaf out, to bloom, to ripen, the trees, the plants, our food.