In a rather creepy crawly episode of Today I Found Out, host Simon Whistler explains the rare but terrifying natural phenomenon of spiders raining down from the sky. Whistler refers to the fact that while spiders cannot fly, they can “balloon” when a good wind catches attached strands of their silk at a high point and sends them aloft. While ballooning happens all of the time, spider rain is quite a bit more rare, but does happen in Australia more than anywhere else. When inclement weather comes along, the spiders get weighed down by falling raindrops that take the spiders to ground.
Worryingly described by entomologists and arachnologists as a “not uncommon” occurrence in certain parts of the globe, spider rain can see anywhere from a few thousand to several million spiders tumble from the sky in a given area, seemingly out of nowhere. …many thousands or millions of spiders will decide to balloon at the exact same time, either because they’re a single colony or because weather conditions force them to. …on rare occasions certain weather patterns can see the millions of spiders floating through the air at any given time being thrown to Earth simultaneously at the same location.
