Residents in Beijing are reporting an unusual increase in snake sightings, with the warmer and more humid weather luring the reptiles into the capital. The encounters have caused concern and surprise among locals.

Residents in some parts of Beijing are on edge as rises in humidity and temperature lure snakes into the Chinese capital, where encounters with the reptiles are usually rare. Concerned residents have been sharing their sightings on social media. “Why are there snakes in Beijing’s parks?” one user posted. “It scared me to death.” In the comments section, many others shared similar experiences, with one woman recounting her shock at finding a snake hiding behind the fridge of her 25th-floor...