Trade: Lowest temperature in Hong Kong on May 10?

Market context

On 10 May 2026, the Hong Kong Observatory will record the lowest temperature for that date in degrees Celsius. The market will settle based on which temperature range bracket contains that minimum reading, drawn from the Observatory's official Daily Extract data once finalised. Settlement occurs at 12:00 UTC on that date, though resolution cannot occur until the Observatory publishes its confirmed daily figures.

Hong Kong's May temperatures typically range between 24–29°C for daily minima, though extremes vary considerably year to year. Historical data shows May minima occasionally dip to 20–22°C during cooler weather systems, whilst heat-driven patterns can keep minimums above 26°C. The current 0% implied probability on the order book suggests traders are pricing in either an extremely narrow or non-existent range at the lower end of plausible outcomes, or that liquidity concentration reflects uncertainty around which specific bracket will ultimately contain the settlement value. This probability formation reflects how the market's order book has been constructed ahead of the event.

Traders monitoring this market should track seasonal weather patterns and any significant atmospheric systems developing in late April and early May 2026. The Hong Kong Observatory's extended forecasts and any tropical cyclone activity in the Western Pacific would serve as key catalysts affecting temperature trajectories. The Observatory's historical data publication schedule and any delays in finalising daily extracts could affect settlement timing, though the underlying temperature reading itself is determined by standard meteorological measurement protocols.

How this market resolves

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.

How to trade this market step by step

The mechanics for trading "Lowest temperature in Hong Kong on May 10?" 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.

1. Sign in on polygram.ink with your email — no full KYC under $1,500 lifetime trading volume.
2. Deposit USDC on Polygon (lowest fees, ~$0.01 per transaction) or Ethereum. Funds credit after 12 confirmations.
3. Pick a side. Buy YES if you believe the event will happen; buy NO if you think it won't. The current YES price reflects the market's collective probability.
4. Size your position. If you stake 100 USDC at 50% YES, you'll receive shares that pay $200 if YES resolves true — a 100% gross return. If NO resolves, your shares are worth $0.
5. Set risk controls (optional). Stop-loss, take-profit, and limit-order types all supported. Use the trade ticket's slippage box to cap your maximum entry price.
6. Wait for resolution. When the event resolves on-chain via the UMA optimistic oracle, the winning side settles to 100¢ automatically and USDC hits your balance within seconds. Withdrawable to any wallet you control.

How active is this market?

$28K 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.

Last 24 hours alone saw $715 in turnover, consistent with the market's lifetime daily-average pace.

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.

Key terms

YES / NO share

A binary outcome token that pays $1.00 if the underlying claim resolves true (YES) or false (NO), and $0 otherwise. The market price between 0¢ and 100¢ is the implied probability.

CLOB

Central limit order book. The matching engine that pairs YES buyers with NO buyers (effectively the same trade). Polymarket's CLOB on Polygon executes trades on-chain via the conditional-tokens framework.

Liquidity

USDC capital sitting in resting limit orders inside the order book. Deeper liquidity means smaller slippage on large trades and a tighter bid-ask spread.

UMA optimistic oracle

The on-chain dispute system that settles each Polymarket market. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution.

Slippage

The difference between the displayed mid-price and your fill price. Affects market orders most; limit orders avoid slippage but may take time to fill.

Conditional token

ERC-1155 outcome share issued by Gnosis Conditional Tokens on Polygon. The token type that resolves to $1.00 or $0.00 at settlement.

See the full prediction-market glossary →

Frequently asked questions

Risk and regulatory note

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.

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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