Trade: Precipitation in Hong Kong in May?
Resolution criteria on PolyGram: This market will resolve according to the total precipitation in mm in Hong Kong between May 1 and May 31, 2026, according to the Hong Kong Observatory. The resolution source for this market will be the Hong Kong Observatory, specifically the "Total Rainfall (mm)" figure for all days in May 2026 under the "Daily Extract" at the https://www.weather.gov.hk/en/cis/climat.htm link once figures are finalized for the specified range. If the reported data falls exactly between two brackets, this market will resolve to the higher bracket. If the relevant data is not available by July 7, 2026, 11:59 PM ET, another credible resolution source will be chosen.
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.
- Liquidity
- $435
- Total Volume
- $2K
- 24h Volume
- $40
- Open Interest
- $685
Market outcomes
| <180mm | 19% YES | 81% NO |
| 180-190mm | 21% YES | 79% NO |
| 190-200mm | 35% YES | 65% NO |
| 200-210mm | 41% YES | 59% NO |
| 210-220mm | 41% YES | 59% NO |
| 220-230mm | 21% YES | 79% NO |
| 230-240mm | 22% YES | 79% NO |
| 240mm+ | 47% YES | 53% NO |
Market context
Hong Kong's rainfall during May 2026 will be measured by the Hong Kong Observatory and reported as total precipitation in millimetres for the calendar month. The current order book on Polymarket implies an 18% probability that May will record measurable precipitation, with traders pricing in relatively dry conditions for the month ahead.
Hong Kong's May climatology shows the territory typically receives between 200–400 mm of rainfall as the pre-monsoon season transitions toward the southwest monsoon. Historical data from the Observatory indicates May ranks among the wetter months, with precipitation occurring on roughly 10–15 days. The 18% implied probability reflects expectations for notably below-average rainfall rather than a completely dry month; traders appear to be pricing in either an unusually early monsoon onset or sustained high-pressure systems that would suppress typical May precipitation patterns.
Traders should monitor the El Niño Southern Oscillation (ENSO) status through early 2026, as La Niña conditions historically correlate with enhanced rainfall across southern China and Hong Kong. The Hong Kong Observatory's seasonal forecasts, typically issued in March and April, will provide updated precipitation outlooks. Additionally, the timing of the southwest monsoon onset—normally occurring in May—represents a critical catalyst; any delays would support the dry-conditions scenario currently priced into the market. Real-time weather pattern developments in April 2026 will be essential for reassessing positioning ahead of the settlement window closing on 31 May.
Wikipedia Context
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FogFog is a visible aerosol consisting of tiny water droplets or ice crystals held in the air near the Earth's surface. Fog can be considered a type of low-lying cloud usually resembling stratus and is heavily influenced by nearby bodies of water, topography, and wind conditions. In turn, fog affects many human activities, such as shipping, travel, and warfare.
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Precipitation (horse)Precipitation was an influential British-bred Thoroughbred stallion who is found in the pedigrees of many racehorses and sport horses today. He is responsible for helping maintain the Matchem sireline through his son, Sheshoon.
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 "Precipitation in Hong Kong in May?" 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.
- Sign in on polygram.ink with your email — no full KYC under $1,500 lifetime trading volume.
- Deposit USDC on Polygon (lowest fees, ~$0.01 per transaction) or Ethereum. Funds credit after 12 confirmations.
- 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.
- 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.
- 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.
- 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?
$2K in lifetime turnover and $435 of resting liquidity puts this market in the below the median by volume for science 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 $40 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.
Frequently asked questions
How does this market resolve?
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.
When does this market close?
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.
How can I trade on "Precipitation in Hong Kong in May?"?
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.
What happens when the market resolves?
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.
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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