"The City of White Rock borders Semiahmoo Bay and is surrounded on four sides by the City of Surrey, British Columbia... White Rock has a moderate climate, with average temperatures of seventeen degrees Celsius in summer and four degrees Celsius in winter. Pilots accustomed to flying around the area often refer to it as 'the hole in the sky', referring to the fact that White Rock is often bright and sunny, while the rest of the Lower Mainland is covered by cloud. White Rock is named for a distinctive large white boulder found on its beach near the promenade: a glacial erratic that migrated south during the last glaciation. The 486-ton granite boulder was kept white by shellfish-eating seabirds, whose guano covered the rock, so much so that sailors in the 19th century used it as a beacon. However, it now remains white through frequent applications of white paint by the city parks department, as it has been a popular graffiti target for over thirty years."