There are tons of different motor oil viscosity grades out there, but which is the right one?  Chances are, your owner's manual is going to tell you.  But that isn't always the case.  In addition, vehicles don't exist in a perfectly climate controlled vacuum.  A vehicle that needs to operate in a frigid Minnesota winter is going to have to work under much different conditions than one running in a Florida summer.  Temperature can make a big impact on what viscosity grade you should consider.  Fortunately, this handy chart can help you make a decision.