The answer to 'why is my spider swarms' is that spider swarms are typically caused by an infestation of spiders in your home or yard. This can happen when spiders find a reliable food source, such as an abundance of insects, and the ideal conditions to build their nests and reproduce. Spider swarms are more common in the warmer months when spiders are more active.
Some common symptoms of a spider swarm include seeing large numbers of spiders in one area, finding multiple spider egg sacs, and noticing an increase in web-building activity. If you're experiencing a spider swarm, it's important to take action to eliminate the problem before it gets out of control.