One example would be the Amondawa who are a group of indigenous peoples of Brazil. The Amondawa are a sedentary group that utilize various forms of hunting fishing and agriculture to provide for their community, yet according to researchers the Amondawa lack an "abstract concept of time."
The University of Portsmouth and the Federal University of Rondonia in Brazil have hypothesized that the lack of the time concept arises from the lack of "time technology" - a calendar system or clocks - and that this in turn may be related to the fact that their number system is limited in detail and only goes up to four.
Amondawa seasons are decided by weather, the changing landscape and by the rhythm of agriculture itself. The irony being that instead of agricultural activities being performed by a season designated by "time", agriculture is an integral part of what actually determines the seasons.
The Amondawa were first "discovered" by anthropologists in 1986 and
according to recent studies the Amondawa language has no word for
"time", or indeed of time periods such as "month" or "year".
Source: Amondawa tribe lacks abstract idea of time, study says
By Jason Palmer, Science and Technology Reporter
BBC News | Science & Environment
Prof Sinha and his team, including a linguist and anthropologist,
spent eight weeks with the Amondawa researching how their language
conveys concepts like "next week" or "last year". There were no words
for such concepts, only divisions of day and night and rainy and dry
Source: Amazonian tribe has no calendar and no concept of time
By Richard Alleyne, Science Correspondent
The Telegraph | Science News
Research team's collective article:
When Time is not Space: The social and linguistic construction of time intervals and temporal event relations in an Amazonian culture.
Article appears in Language and Cognition, 3(1): 137-169.
Chris Sinha (University of Portsmouth)
Vera da Silva Sinha (University of Portsmouth)
Jörg Zinken (University of Portsmouth)
Wany Sampaio (Federal University of Rondônia)