This site provides a tool to count the number of any selected day of the week over an entire year. You can pick any year and find out things like the number of Sundays in 2020.
Don't forget to check out the other date calculator tools available on the site, like the Days From Today calculator that helps you find the date occurring exactly X days from now. Or if you're trying to count the total number of days between two dates, you can use the Date Difference calculator.
Today is Thursday, December 3rd, 2020. It is the 338th day of the year, and in the 49th week of the year (assuming each week starts on a Monday). There are 31 days in this month. 2020 is a leap year, so there are 366 days in this year.