How many weeks from January to March?

Answer 1

Including January and March, it's 13 weeks. In regular years it is 12 weeks and 6 days, and in leap years it is exactly 13 weeks.

If referring to the period from the beginning of January to the beginning of March or from the end of January to the end of March (or middle to middle, etc.), it is eight weeks and three days in regular years and eight weeks and four days in leap years.