Resolution criteria on PolyGram: This market will resolve to the temperature range that contains the highest temperature recorded by the Hong Kong Observatory in degrees Celsius on 21 May '26. The resolution source for this market will be information from the Hong Kong Observatory, specifically the "Absolute Daily Max (deg. C)" the specified date once information is finalized in the relevant "Daily Extract", available here: https://www.weather.gov.hk/en/cis/climat.htm This market can not resolve to "Yes" until data for this date has been finalized. The resolution source for this market measures temperatures in Celsius to one decimal place (eg, 9.1°C).
Real-money prediction markets aggregate live odds from thousands of traders, surfacing a sharper probability than any single forecast. Odds will populate live once the order book fills resolving today, backed by $322K of resting liquidity.
PolyGram is an on-chain prediction market where you trade YES or NO outcome shares with real USDC on Polygon. For this market, buy YES if you believe the event will happen, or NO if you think it won't. Your maximum loss is your stake — winning shares pay $1.00 each at resolution. Unlike sportsbooks, there is no house edge: prices are set by supply and demand from other traders and reflect the crowd's real-time probability.
Market outcomes
| 22°C or below | 0% YES | 100% NO |
| 23°C | 0% YES | 100% NO |
| 24°C | 0% YES | 100% NO |
| 25°C | 0% YES | 100% NO |
| 26°C | 0% YES | 100% NO |
| 27°C | 0% YES | 100% NO |
| 28°C | 0% YES | 100% NO |
| 29°C | 0% YES | 100% NO |
Hong Kong’s maximum temperature on 21 May will be set by the Hong Kong Observatory’s final daily extract, using the “Absolute Daily Max (deg. C)” for that date. The market is currently pricing 0% YES, which in Polymarket terms means the order book is showing no visible willingness to pay for the outcome at present, so the implied probability is being formed almost entirely by the absence of bids rather than by an active consensus that the temperature cannot fall in range.
For context, late May in Hong Kong is already in the warm season, but the city can still see a broad spread of outcomes depending on cloud, rain and maritime flow. AccuWeather’s May 2026 outlook shows daily highs roughly in the low-80s to mid-90s Fahrenheit, which translates to about 28–34°C, while Climate-Data’s May profile points to the warmest 10-day period being the last third of the month, with average highs near 26°C. Last year’s Hong Kong Observatory summary described May 2025 as relatively dry and hot, with a monthly peak of 33.0°C on 22 May and rainfall far below normal, illustrating how quickly readings can move above seasonal averages when the subtropical ridge strengthens.
Traders should watch the Observatory’s afternoon readings, the final published daily extract, and any short-notice rain or thunderstorm warnings that could suppress the daytime high. The key dependency is the weather through the late-morning to early-afternoon period before the 12:00 UTC settlement window closes, because a late surge or a passing shower can shift the day’s maximum by several degrees. Recent official and third-party forecasts suggest a warm regime is more likely than a cool one, but the market will still depend on the actual final number published by the Hong Kong Observatory rather than on forecast ranges.
Resolution is handled by the UMA optimistic oracle on Polygon. A proposer submits the outcome, a two-hour dispute window opens, and if no one stakes a counter-claim the payout is final. Contested outcomes escalate to UMA token-holder voting. Payouts clear in USDC to the winning side.
For this market, the resolution date is 21 May 2026. A UMA proposer can submit the outcome from that moment; the two-hour dispute window closes at , and assuming no counter-claim is staked, winning USDC clears to trader balances by approximately .
If a dispute is filed inside the two-hour window, the outcome escalates to UMA token-holder voting, which extends settlement by roughly 48 hours. This particular market has no public resolution feed listed; disputes here are more likely if the underlying outcome is subject to interpretation, in which case the UMA token-vote arbitrates the wording of the original market question.
Withdrawal pace from your PolyGram balance is non-custodial and immediate — once payout clears, funds are yours to send to any Polygon wallet you control. Funds clear directly to your in-app USDC balance on Polygon. Withdrawals are non-custodial: send to any address you control, typical confirmation under 30 seconds, gas paid in USDC if you'd rather not hold MATIC.
Minimum order size on PolyGram is $1.00, with no maximum cap aside from available book depth. Orders route into Polymarket's on-chain CLOB on Polygon; the matching engine pairs YES buyers with NO buyers atomically — every executed trade is settled on-chain with no counterparty risk. For "Highest temperature in Hong Kong on May 21?", order-book behaviour for this market reflects the underlying volatility of the outcome — patient limit orders typically fill closer to mid than market orders.
The trade ticket includes a slippage box (default 2%, configurable 0.1%-10%) that caps the worst-case entry price. Your maximum loss is your stake — winning YES (or NO) shares pay $1.00 each at resolution. With this market's current book depth ($322K of resting liquidity), a $500 order should fill with single-cent slippage at the displayed mid-price.
PolyGram charges 0% house edge — no spread mark-up, no rake on winnings, no withdrawal fees beyond network gas. The platform earns exclusively from optional features (copy-trade boosts, advanced order types, the yield vault on idle USDC); the trading surface itself is at-cost.
The mechanics for trading "Highest temperature in Hong Kong on May 21?" are the same as any other PolyGram event contract. Each YES share resolves to $1 if the event happens, or $0 if it doesn't. The current price between 0¢ and 100¢ is the market's probability estimate, set live by the order book.
$213K in lifetime turnover and $322K of resting liquidity puts this market in the top 10% by volume for weather contracts on PolyGram. Order-book depth is exceptional — among the deepest order books in the category.
Last 24 hours alone saw $201K in turnover, well above the lifetime daily-average for this market — a clear sign of news catalysing trader activity right now.
The market has been open for under a month — fresh enough that information asymmetry remains a real factor.
Higher-volume markets tend to have tighter spreads and faster price discovery — meaning the displayed YES/NO percentages are more likely to reflect the true crowd-implied probability rather than a single trader's directional view.
Resolution is handled by the UMA optimistic oracle on Polygon. A proposer submits the outcome, a 2-hour dispute window opens, and if uncontested the payout is final. Contested outcomes escalate to UMA token holders.
This prediction market is scheduled to close on 21 May 2026. After the resolving event occurs, settlement typically clears within 24 hours once the UMA optimistic oracle confirms the outcome. All payouts are in USDC on the Polygon network.
To trade on this prediction market, create a free PolyGram account at polygram.ink, deposit USDC via Polygon, and place a YES or NO order on the outcome you believe in. You can learn more on our how-it-works page. Your maximum loss is limited to your stake — there is no leverage or margin.
When the outcome is determined, winning YES shares pay out $1.00 each in USDC, while losing shares pay $0. Settlement is handled by the UMA optimistic oracle on Polygon — a proposer submits the result, a two-hour dispute window opens, and if uncontested, payouts are distributed automatically. You can withdraw your winnings to any Polygon wallet.
Prediction-market positions can lose 100% of staked capital. Outcomes are uncertain by definition — historical accuracy of crowd-implied probabilities is high in aggregate but not for any single market. PolyGram does not provide investment advice. Trade only with capital you can afford to lose. For "Highest temperature in Hong Kong on May 21?", the considerations above apply directly — Trade size should reflect the binary nature of the payoff: even a 70% probability event resolves NO 30% of the time, so any single position can lose 100% of staked capital.
Regulatory status varies by jurisdiction. Germany, the United States, and most EU countries treat Polymarket-style event contracts under one of three frameworks: financial derivative, gambling product, or unregulated novel asset. Consult local counsel before trading.
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