Periodic tense is a subtype of the grammatical category of tense, which encodes that the event expressed by the verb occurs within a particular period of the day (such as 'at night', 'in the morning' etc.) or of the year ('in winter', 'in summer' etc.). Its does not encode a relation to a particular point of reference, unlike deictic tense, the grammatical expression of time reference (usually past, present or future) relative either to the moment of speaking (absolute tense) or to another point of reference (relative tense).

Periodic tense is geographically restricted to Northern America, the Western Amazon region, the Sepik region, Arnhem land and it is almost entirely absent from languages of Africa and Eurasia, which the exception of Chukotkan languages.

Periodic tense can be illustrated with data from Nez Perce, which has one of the richest paradigms, comprising matutinal, diurnal, vesperal, nocturnal and hivernal, as illustrated in the following examples

méy-tip-se

MAT-eat.meal-PRS:SG

méy-tip-se

MAT-eat.meal-PRS:SG

'I am having breakfast.'