Trelawney once predicted that Harry was born in midwinter, while born in July. - But it turns out that Harry was a Horcrux and a part of Voldemort lived inside of him; Voldemort was born on 31st December.

In Deathly Hallows, the stunt director had to get the snatchers to speed up during the chase scene in the forest because Daniel Radcliffe, Emma Watson and Rupert Grint ran much faster than expected.