A study was conducted to examine the relationship between the "climate" of physical education classes and students' formative evaluation of the classes. Through analysis of this relationship, we clarified the importance of "climate" for effective physical education. The data were collected by observing 59 physical education classes in elementary schools. The instrument for observing students' human relationships and affective behavior developed by Hirano et al. was employed, and the results were assessed using the scale of students' formative evaluation of physical education classes developed by Takahashi et al. The main findings were as follows: 1) Positive human relationship behavior and positive affective behavior were significantly correlated with students' formative evaluation in both ball game and gymnastics classes. 2) In ball game classes, negative human relationship behavior and negative affective behavior were negatively correlated with students' formative evaluation. 3) Thus, it was confirmed that the learning results were influenced as much by "climate" as by "momentum".