Unlike the number of days that changes the number of weeks in a year never changes.
The number of Weeks in a year is usually and always 52.

Although there are 52 weeks in a year. but it is not so true.
if we multiply 52 by 7 then ans is 364 i.e 52*7=364. but in a year there are 365 days and in leap year 366 days.

if we consider 52 weeks then the number of days in year are 364. so the real answer is that, in normal year there are 52 weeks and one day and in leap year 52 weeks and Two days.

See the calculation below.

One calendar common year has 365 days:

1 common year = 365 days = (365 days) / (7 days/week) = 52.143 weeks = 52 weeks + 1 day

1 leap year = 366 days = (366 days) / (7 days/week) = 52.286 weeks = 52 weeks + 2 days