When grown under cool temperature, winter annuals respond with not only enhanced freezing tolerance but also photosynthetic upregulation. The role of the cold-induced C-repeat-Binding Factor (CBFs) in long-term maintenance of freezing tolerance and photosynthetic upregulation was examined in two Arabidopsis thaliana ecotypes adapted to differing climates (Italy = IT and Sweden = SW) as well as corresponding CBF-disabled mutant lines. Data on photosynthetic, morphological, and freezing-tolerance phenotypes as well as transcriptomic data were collected from plants grown for several weeks under controlled conditions with several combinations of temperature and light levels. Freezing tolerance in these acclimated plants depended strongly on CBFs in both SW and IT. In contrast, photosynthetic upregulation was the same, or modestly reduced, in cbf mutant versus parental lines of SW and IT, respectively. Physiological and transcriptomic data showed a consistent trend for a greater role of CBFs in cool-temperature-grown plants of IT versus SW. These features suggest that IT remained in a state of continuing CBF-related cold-acclimation even after weeks of acclimation, while SW entered a state of completed acclimation in which maintenance of photosynthetic upregulation no longer required CBF activation and maintenance of freezing tolerance was less dependent on CBF than in IT.