Quiahuitl, rain, gives with one hand and destroys with the other, and the tonalamatl kept both in view: Sahagun's fourth book makes 1 Quiahuitl a day of sorcerers, on which the nanahualtin, the shape changers of Nahua belief, were said to be born, and the rain days generally read as troubled and touched by illness, an unfavourable augury that draws on storm's genuine capacity for damage rather than only its more usual association with needed water for crops. This darker reading of a sign whose element, rain, is elsewhere in the count treated favourably through its governing deity's more benevolent aspects shows how thoroughly the tonalpohualli's readers separated a sign's raw natural symbol from any single fixed moral valence, since the same rain that nourished fields in Tlaloc's more usual character could, read here through the day sign's own name, also carry storm, flood and the uncanny company of shape changers.
The sign's association with sorcery placed it among the handful of days the tonalpouhque treated with particular caution when advising on the timing of ordinary undertakings, a caution the sign shares with its own trecena, Trecena 7, whose overall augury as the sorcerers' week the day sign's individual reading reinforces directly.