The Perseid meteor shower forms when the Earth passes through a plume of dust particles released by Comet Swift-Tuttle. They burn up in the Earth's atmosphere at an altitude of 80 to 100 kilometres and form bright trails - the so-called "star rain".
According to the International Meteor Organisation (IMO), with a perfectly clear dark sky, 50 to 75 meteors per hour can be seen falling during Perseid's peak.