Black and yellow garden spider. Garden Spiders are found throughout the United States. They are also known as the Writing Spider, Banana Spider, and Corn Spider. Their black, yellow and white markings are conspicuous. The females are the larger of the sexes, measuring about 3/4 of an inch. The Garden Spider is completely harmless to humans.
I *think* this one's a Neoscona Arabesca. Anyway, it's very like the ambitious daughters of Arachne who build nets across my screen doors every year. Beautiful ladies, even if they haven't managed to realise that the only game on this trail is human.