The longitudinal changes of the average grades in four study semesters before and during the COVID-19 pandemic and distance learning are presented in the current study. 11th grade students' (n=586; age M=17.38, SD=0.53) average grades were assessed, as well as their verbal and non-verbal reasoning abilities, and self-evaluations of problem-solving and self-management skills. The main findings of the study are: (1) There is a general pattern for the grades to increase during the four semesters from the autumn 2019 to the spring 2021; (2) The general tendency of changes in the grades is similar to various students' groups based on their level of skills; (3) Higher level of students' skills and cognitive abilities determined that students' grades were higher and were more likely to increase during the "second wave of the pandemic", compared to the middle and low-level skill groups. Results of the current study show a tendency for the average grades to increase during the pandemic and distance learning, however, there are group differences in the findings, relating the grade level to the individual level of students' skills and abilities.