In Zurich, spring’s arrival isn’t predicted by a furry, shadow-gazing rodent peeking out of his hole. No, that’s obviously too silly of a tradition for the Swiss. They use a much more scientific method, one that involves… lighting a giant snowman on fire and timing how long it takes for his head to explode. Really.

Sechseläuten is one of Zurich’s signature holidays, with festivities lasting the entire weekend leading up to the main event (which usually falls on the third Monday in April). The festivities are run by the guilds, fancy clubs whose membership used to be based on the crafts that men (not women) learned – essential, vital crafts such as pretzel-making and beer brewing. While in medieval times the guilds used to form part of Zurich’s government, the current-day versions are often criticized as being nothing more than exclusive clubs for the rich; membership is primarily passed down from one generation of Zurich’s upper class to the next.

Monday afternoon there is a large parade of guild members and their bands, decked out in their finest period costumes and waving their colorful guild flags. The women (who are mainly relegated to the role of spectator) sit on the side of the parade route with large baskets of flowers, which they hand out to all their favorite parade participants.

But all this is just a precursor to the real excitement of the day: the burning of the Böögg. The Böögg, a snowman-like figure constructed out of plaster, paint, chicken wire, and explosives, is mounted high atop a burnable structure in the middle of small field in front of the opera house. At precisely 6 PM, the structure is set on fire, and the enormous surrounding crowd grows hushed as it counts down the minutes until the flames reach and consume the Böögg’s explosive-filled head. The longer it takes for the head to explode, the colder and gloomier summer will be. And that, ladies and gentlemen, is how you predict the end of winter.