Russian Days of the Week

Did you know that we use the Accusative case with the days of the week (“On Monday, on Tuesday”, etc) and the Dative case when we mean regular actions (“On Mondays, on Tuesdays”, etc.)?

For example,

В понедельник я полечу в Москву. On Monday I will be flying to Moscow.

По средам мы ходим гулять в парк. On Wednesdays we go for a walk to a park.

В эту пятницу у меня нет уроков. I don’t have lessons this Friday.

По субботам они посещают музеи. They visit museums on Saturdays.