The article discusses the temperatures of the main ethnic groups in the Baltic states: Estonians, Latvians, Lithuanians, and their three Russian-speaking communities, and the Latgalian and Polish minority groups in Latvia and Lithuania, respectively. The study uses a triangulated methodology that includes a survey questionnaire for quantitative study and an associated protocol for a semi-structured focus group interview. The aim of the methodology is to make the notion of ethnic temperature quantitatively assessable, while retaining the opportunity for a rich qualitative description to understand its nature. The quantitative analysis confirms the wide divergence of subgroups within each ethnic group, each of which has a different ethnic temperature. The (intergroup) interaction of the members of these subgroups influences both the average temperature of the in-group and the temperatures of significant out-groups. The findings are interpreted to forecast the nature of ethnic processes in the Baltic states.