Best way to clean outside windows which are on a second story?

I use a squeegee washer on a light weight extended pole.

Assuming your windows do not fold in / swing in what we used to do was first get a small ladder. Wash the window on the inside as thoroughly as you can. Pull the top half of the window down. Carefully standin on a firm foundation, ladder, pull the top half down. Lean over it and wash the outside of it. With the top half down carefully pull up the bottom half. Again, carefully lean out and wash as much of the outside of the bottom half as you can. Pull up the top half completely then the bottom half  as far as possible letting you reach under it and clean the outside half you could not previously reach. I know it sound complecated but it can be done.