"1637 calli Xihuitl ipan in ocepayauh huel chicahuac (p. 730)" = "1637 House year. In this year it snowed very hard." (Anales de Tlaxcala, no. 2, 1519–1692)
Frances Krug, "The Nahuatl Annals of the Tlaxcala-Puebla Region," ch. 2, pp. 78–79, Ph.D. Dissertation draft written in the 1980s, with transcriptions and translations approved by James Lockhart. Cited here by SW.
cepayahui = to snow (central Mexico, 1613)
Annals of His Time: Don Domingo de San Antón Muñón Chimalpahin Quauhtlehuanitzin, James Lockhart, Susan Schroeder, and Doris Namala, eds. and transl. (Stanford: Stanford University Press, 2006), 234–235.
ypan nahui ora peuhqui quiyahuitli Lones cemilhuitli cepayauh = at 4 o’clock it began to rain. On Monday it snowed all day.
Here in This Year: Seventeenth-Century Nahuatl Annals of the Tlaxcala-Puebla Valley, ed. and transl. Camilla Townsend, with an essay by James Lockhart (Stanford: Stanford University Press, 2010), 178–179.