This market asks whether Hong Kong's daily high temperature on May 2 will remain at or below 21°C—a threshold well below the typical early May average of 26–28°C. May marks the transition from spring to early summer in Hong Kong, with warming trends and increased humidity as the region moves toward the summer monsoon season. The 0% YES odds reflect strong trader consensus that cooler weather is extremely unlikely this late in the season. Hong Kong Observatory's official daily maximum temperature reading will determine the outcome. Traders pricing this near zero indicate confidence in at least typical seasonal warmth, if not above-normal heat.
Deep dive — what moves this market
Hong Kong's climate in early May sits at a critical seasonal inflection point. The subtropical location, positioned at approximately 22 degrees north latitude, experiences rapid warming from late spring into summer, with average daily highs in the mid-to-upper 20s Celsius and steadily increasing humidity as moisture-laden air masses advance northward. A maximum temperature of 21°C would represent a striking deviation below normal—roughly 5–7 degrees cooler than historical May averages—occurring only under highly unusual meteorological conditions such as a rare cold front penetration, a tropical depression bringing heavy cloud cover, or an anomalous large-scale wind shift. The current 0% YES odds reflect trader conviction that such a cool outcome is implausible for this date in May. Market prices incorporate baseline seasonal climatology: Hong Kong is rarely cool by this time of year, and the atmospheric setup in early May overwhelmingly favors warming as solar radiation strengthens and the Pacific High expands northward. Historical context strongly supports the market's pricing. May temperature extremes in Hong Kong show that daily highs below 21°C are exceptionally rare—recorded fewer than 2–3 times per decade. Over the past 30 years, May 2 specifically has never recorded a high below 24°C, with readings typically clustering between 26–29°C. This historical precedent anchors trader expectations and helps explain the market's extreme confidence in the NO outcome. To resolve YES, the region would need an unexpected significant weather system—perhaps an early monsoon trough or rare cool air intrusion—scenarios traders view as implausible given seasonal dynamics. The traders' pricing suggests they see no credible catalysts for anomalously cool temperatures. This is a classic seasonal market where trader conviction aligns with historical climate patterns.
What traders watch for
Hong Kong Observatory official daily maximum temperature reading for May 2, 2026
Any tropical weather system developments May 1–2 (depressions, monsoon shifts, cloud cover)
Upper-level wind pattern changes that could deliver cooler air to the region
Seasonal thermal baseline—May typically averages 26–28°C, roughly 5–7°C above the 21°C threshold
How does this market resolve?
Market resolves YES if Hong Kong's official high temperature on May 2 is 21°C or below; NO if above 21°C. Hong Kong Observatory's official daily reading determines the outcome at market close.
Prediction markets aggregate trader expectations into real-time probability estimates. On Polymarket Trade, 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. This page summarizes the market state for readers arriving from search; for live trading (place orders, see order book depth, execute a trade) open the full interactive page linked above.
