The purpose of this study is to explore students' understanding levels and misconceptions about temperature and factors affecting it. The concept of the study was chosen from Geography National Curriculum. In this study, a questionnaire was developed after a pilot study with an aim to ascertain the students' understanding levels of temperature and factors affecting it. The questions in the questionnaire were in the form of open-ended questions and short-answers. The questionnaire was applied to 100 students who were selected on a random basis. The students were at 9th grade, and their age group was between 14 to 15. The sample was chosen from high schools in the City of Trabzon. At the end of the study, it is revealed that the students did not understand the concept of temperature and factors affecting it sufficiently, and they have a lot of misconceptions about these. In the study, since there has not been success both in teaching and learning of this concept, it is recommended that both curriculum development experts and teachers be engaged in the teaching of this concept. (Contains 1 table and 1 figure.)