Tiny red spiders that are approximately the size of a pin's head are called clover mites. They are most commonly seen in the spring, but infestations can occur in the fall.
Clover mites live in grass, but they occasionally find their way inside homes. They do not bite, and they cannot harm people or animals. To get rid of them, it is vital to close off their entry points and remove any existing mites.
Windows, doors and cracks are common entry points for clover mites, so homeowners should close off or caulk all of these areas. Existing mites can be vacuumed up using a shop vacuum, and commercial pesticide spray can be used to kill clover mites that are not accessible with the vacuum.