Resolution criteria on PolyGram: This market will resolve to the temperature range that contains the lowest temperature recorded by the Hong Kong Observatory in degrees Celsius on 31 May '26. The resolution source for this market will be information from the Hong Kong Observatory, specifically the "Absolute Daily Min (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 until data for this date has been published. The resolution source for this market measures temperatures in Celsius to one decimal place (eg, 9.1°C). Thus, this is the level of precision that will be used when resolving the market.
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 (the resolution date has passed — final payout is being settled via UMA oracle).
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
| 20°C or below | 0% YES | 100% NO |
| 21°C | 0% YES | 100% NO |
| 22°C | 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 | 100% YES | 0% NO |
On 31 May 2026, the Hong Kong Observatory will record the lowest temperature for that day, measured to one decimal place in degrees Celsius. This market will settle based on which temperature range bracket contains that official reading, with the current order book implying zero probability for YES outcomes across all ranges. The settlement window closes at noon UTC on 31 May, after which the Observatory's published daily extract data becomes the binding resolution source.
Hong Kong's late May climate is characterised by warm, humid conditions as the region transitions into summer. Historical data shows daily minimum temperatures in late May typically range between 24–27°C, with readings below 22°C exceptionally rare during this period. The 0% crowd probability reflects the seasonal expectation that temperatures will fall within normal warm-season bounds rather than experience anomalous cooling. Comparable May datasets from the Observatory show consistent patterns across decades, providing a stable baseline for assessing whether any given range represents a statistical outlier.
Traders should monitor seasonal weather patterns and any unusual atmospheric developments in the weeks preceding late May 2026. The South China Sea monsoon transition and potential tropical systems could theoretically depress temperatures, though such events remain probabilistically unlikely for this specific date. The Observatory's daily extract publication schedule is the critical dependency; without confirmed official data, the market cannot resolve. Current pricing suggests the crowd expects conventional late-spring conditions to persist through the settlement date.
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 31 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 "Lowest temperature in Hong Kong on May 31?", 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 ($0 of resting liquidity), a $50 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 "Lowest temperature in Hong Kong on May 31?" 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.
$35K in lifetime turnover and $0 of resting liquidity puts this market in the around the median by volume for weather contracts on PolyGram. Order-book depth is thin — large orders may need to be split across the book or executed as limit orders.
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 31 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 "Lowest temperature in Hong Kong on May 31?", 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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