Instead of looking at it on a daily count, look at it as 3-4 hours of reading/studying for every 1 hour of class.
It really varies a lot from semester to semester and depends on which law student (some study a whole lot more than others) and whether you consider student org activities or independent writing projects part of studying. There are some days where I start at 6-something AM and other than a short break to eat and such keep at it till about midnight, there are other days where I do almost no work outside class. Overall though law school takes a lot of time and is a major commitment. I wouldn't plan on much of a life outside of law school:)