The corresponding Maya day is Kawak, in Yucatec Cauac, meaning storm or thunder, and its glyph is the standard sign for a rain cloud and also for stone; it is associated with the rain deities, the Chaks, with thunder and lightning, and with the mountains where rain gathers. The Aztec equivalent day is Quiahuitl, rain. In highland practice the corresponding day is connected with the ancestors, with women and with the healing role of the midwife. The Dreamspell reading of catalysis and self-generation keeps the disruptive force of the storm and drops the rain, which in an agricultural society is the point of a storm; that inversion, from the giver of water to the agent of upheaval, is worth noticing.
Cauac is the nineteenth of the twenty authentic Tzolk'in day signs, its imagery storm and renewal; the living K'iche' daykeeping tradition knows the corresponding day as Kawoq, meaning storm or rain, closely matching Cauac's own sense. In the directional scheme, Cauac belongs to the west and the colour black. Arguelles's Solar Seal 19, Blue Storm, borrows Cauac's storm imagery directly and closes the Dreamspell's nineteenth wavespell before Solar Seal 20, Yellow Sun, completes the sequence, mirroring the way Cauac stands second-to-last among the twenty authentic Tzolk'in day signs before Ahau closes that count.