This is a female orb weaver of some sort (possibly in the Araneus genus).

The abdominal pattern seems potentially distinctive, so one of our experts might be able to classify it to a genus (or maybe even a species)... however, identifying most orb-weavers of this sort into a specific genus/species can be very difficult except with a microscope (by an expert).

What I can tell you is that she is harmless to people, so definitely observe her. She'll weave large, ornate, orb-shaped webs, and will most likely be in the center of the web at night. During the day, she'll move off to the web and hide nearby in some cover (leaves, branches, debris). While hiding, she'll will monitor her web with a trapline (signals when something is disturbing the web). It's a fascinating spider to watch!!