These are “Orb Weaver” spiders. They are large (about 1/2” to 3/4” body length), and they usually appear in late summer and early fall. Right about now, in other words. This is their time of year to build webs and find mates.

They are 99% HARMLESS TO HUMANS. THEIR VENOM IS NON-TOXIC TO US. THEY ARE DOCILE AND NON-AGGRESSIVE. THEY ALMOST NEVER, EVER EVEN BITE!!!!

I know they’re scary looking, but they are our allies, not enemies. They devour insect pests that plague us. Also, they're mostly active at night - they rest in their webs during the day.