Hong Kong's climate in May is characteristically warm and humid, with average daily highs typically ranging from 28–30°C and lows around 23–25°C. A maximum temperature of 19°C or below would represent an exceptionally rare and dramatic cold event—approximately 10 degrees Celsius cooler than seasonal norms. The current 0% odds reflect overwhelming trader conviction that such a scenario is essentially impossible. For such extreme cold to occur in mid-May, Hong Kong would require an unusually strong cold front pushing southward from mainland China, combined with sustained high pressure over the region—a weather pattern that seldom manifests during late spring. Instead, May's weather is typically dominated by warm southwesterly winds delivering tropical air masses from Southeast Asia, gradually intensifying ahead of the Southwest Monsoon transition season. The market resolves using official Hong Kong Observatory temperature readings for May 17. The virtually zero odds suggest traders are confidently pricing in continuation of normal seasonal patterns and entirely discounting any possibility of an anomalous frigid day during what is typically one of Hong Kong's warmer months.
What factors could move this market?
This market captures a boundary-condition weather scenario where the collective trader forecast is firmly anchored on seasonal climatology. Hong Kong's subtropical location and proximity to tropical waters of the South China Sea ensure that even during May's transition period, the territory experiences predominantly warm conditions. Historical temperature records show that daily highs below 20°C are virtually nonexistent in May; the lowest ever recorded high temperature in May across Hong Kong's weather station history would likely be in the low-to-mid 20s Celsius. The 19°C threshold represents an extreme outlier scenario that would rank among the five coldest May days on multi-decade records. The zero odds pricing reflects trader understanding that this outcome requires multiple coinciding atmospheric anomalies: a powerful Siberian or Mongolian high-pressure system, a deep trough penetrating far southward, and timing that delivers the coldest air precisely on May 17. The climatological probability of such an event is extremely low, perhaps less than 0.5% in any given May. Several weather factors could theoretically push Hong Kong toward cooler conditions: an early-season northeasterly surge from a dissipating cold front, unusual upper-level divergence patterns, or rare atmospheric anomalies. However, the seasonal transition in May typically suppresses these mechanisms. Conversely, factors driving the consensus warm outcome include strengthening solar forcing as northern hemisphere summer approaches, the warming influence of tropical ocean currents, and the climatological dominance of warm southwesterly flows during late spring. Recent climate data show no systematic trend toward May cold events in Hong Kong; if anything, May temperatures have gradually warmed relative to historical baselines. The spread between YES and NO odds illustrates near-perfect trader conviction. When a market reaches 0% on a tail-risk outcome, it signals that participants view the scenario as outside the reasonable bounds of seasonal weather variability. This mirrors how insurance contracts price catastrophic but unlikely events at the edges of historical experience. The $7,733 liquidity and $1,100 daily volume suggest modest participation in this recurring weather market, appropriate for a daily recurring event with limited stakes.
What are traders watching for?
May 17 08:00 HKT: Official Hong Kong Observatory publishes the day's high temperature reading; this single measurement determines market resolution.
May 16 evening: Weather forecast models finalize their May 17 predictions; watch regional meteorological charts for any unexpected cold-air anomalies.
May 17 daytime: Real-time temperature monitor shows hourly highs; extreme-weather scenarios might briefly approach 19°C before final daily maximum.
Historical precedent: Hong Kong's lowest recorded May high temperature; traders may reference this baseline to justify the 0% odds conviction.
How does this market resolve?
Market resolves based on the official Hong Kong Observatory's recorded maximum temperature for May 17, 2026. YES if the high is 19°C or below; NO if it exceeds 19°C.
Polymarket Trade is an independent third-party interface to the Polymarket CLOB prediction market exchange on Polygon — not affiliated with Polymarket, Inc. Prediction markets aggregate trader expectations into real-time probability estimates. Every market question resolves YES or NO based on a specific event outcome; traders buy shares of the side they believe will resolve positively. Prices range 0¢ (certain no) to 100¢ (certain yes) and naturally reflect the crowd-implied probability of YES. Polymarket Trade is non-custodial — your funds never leave your wallet. Open the full interactive page linked above to place orders, see order book depth, and execute a trade.
