It can be difficult to ID some spiders from the underside, especially when the top and bottom are so different from each other. But this spider is the black and yellow garden spider, just one of the common names for Argiope aurantia

She is one of the most beautiful creatures in the garden, and often found near our homes. Since she's diurnal, we get to observe her during the day.....toss a live insect into the web and watch the action.

Thank you for the ID. What you can't see from the picture, is that there are actually 3 spiders in a row, each web behind the other. The other two are similar size, but brown. They must think that's a great hunting spot!