Static typing means you know the type of something at compile time. Dynamic typing means you don't. The upside to dynamic typing is that the compiler doesn't have to prove much about your program; the downside is that it can't really prove much of interest either. Strong vs weak typing is about how much your language is willing to fudge types in order to make an operation succeed without errors -- be it the intended result or not. Both static and strong typing tend to make errors be more obvious sooner. Both dynamic and weak typing tend to require less boilerplate to make your program do things.
Python doesn't know the types of things in advance (dynamically typed), but it is very picky about which types are allowed to interact (strongly typed). Even in cases where the answer is obvious, like str.join, you still have to make everything strings: "".join([1, 2, 3]) will fail.
To demonstrate why these are orthogonal, consider the other cases.
Haskell is strongly and statically typed. A program that adds a string and a number together will be rejected at compile time because the compiler can prove it's invalid.
C is weakly and statically typed. A program that combines a string and a number may be accepted by the compiler, who interprets the number as, I dunno, a wchar_t or something. Another example of weak typing is how C allows (heck, encourages) pointer arithmetic and untagged unions/structs.
JavaScript is weakly and dynamically typed. A program that adds a string and a number together will, at runtime, convert the number to a string and then concatenate the two.