The Half Moon Bay Art and Pumpkin Festival has run on the third weekend of October every year since 1971 and is the town's defining event. It shuts down Main Street for two days for stalls, music stages, a parade, and pumpkin-themed everything (pies, ales, pancakes, beauty contests for pets in costume). About 250,000 people pass through across the weekend, which is roughly twenty times the town's population.
The undisputed centrepiece is the Safeway World Championship Pumpkin Weigh-Off, held on the Monday before the festival at IDES Hall on Main Street. Growers from across North America haul their year-long monsters in on flatbed trucks, the pumpkins are lifted onto a giant scale by forklift, and the heaviest takes a cash prize that is now well over $30,000. Recent winners have been over 1,000 kilograms, with the world record broken several times in the last decade. The weigh-off itself is free and open to the public — if you can only see one piece of the festival, this is it.