Platform comparison
| Platform | YES odds | NO odds | Fee | KYC | Settlement | |
|---|---|---|---|---|---|---|
Polymarket (via BTC Prediction) Pick polygram.ink (preferred broker) |
46% | 54% | 0% (USDC on-chain) | No-KYC up to $1,500 | USDC, auto via UMA oracle | Open live market → |
Polymarket (direct) polymarket.com |
46% | 54% | 0% | Geo-blocked in US/UK/EU | USDC, on-chain | Open live market → |
Kalshi kalshi.com |
— | — | Up to 7% per trade | US-only, KYC required | USD | Open live market → |
Betfair Exchange betfair.com |
— | — | 2-5% commission | Full KYC from first trade | GBP / EUR | Open live market → |
Manifold Markets manifold.markets |
— | — | Play-money (mana) | None — play-money | Mana (no cash-out) | Open live market → |
Outcome probabilities
Current market-implied probability for each outcome, from the live order book.
| Outcome | Probability |
|---|---|
| 27°C | 46% |
| 28°C | 40% |
| 29°C | 10% |
| 30°C | 5% |
| 26°C | 4% |
| 31°C | 1% |
| 22°C or below | 0% |
| 23°C | 0% |
| 24°C | 0% |
| 25°C | 0% |
| 32°C or higher | 0% |
Market context
The contract turns on the **single highest daytime temperature** the Hong Kong Observatory records for Hong Kong on 1 August 2026, then settles in USDC according to the market’s temperature band. August in Hong Kong is normally hot and humid, with typical afternoon highs around 31–32°C, and the Observatory’s published climatology shows that late-summer readings can still reach the mid-30s in strong heat events.[1][10][12]
The current **0% YES** crowd price is most naturally read against the fact that 1 August is just one day, not a whole month: even in very hot years, the daily maximum has to clear the relevant band on that date specifically. Comparable August extremes show the city can spike sharply, with the Observatory recording 36.3°C on 8 August 2015, while 2024 reached 35.4°C on 5 August and 2025 peaked at 31.9°C for the month, illustrating how quickly outcomes can range from ordinary to exceptional depending on cloud, rain and synoptic flow.[9][11][5]
For traders, the key catalysts are the Hong Kong Observatory’s morning-to-afternoon weather updates, typhoon or rain alerts, and any late shift in the regional pressure pattern that would suppress or amplify the day’s maximum. Because the market resolves from the Observatory’s final Daily Extract rather than an intraday estimate, the practical watchpoints are the published observation cycle, the final daily maximum in Celsius to one decimal, and whether any storm-driven disruption pushes the reading away from the hotter August baseline.[10][2]
Methodology
Methodologically this overview focuses on on-chain pricing: Polymarket's live mid comes from the Polygon conditional-token order book and settles automatically in USDC. The other three venues — Kalshi, Betfair, Manifold — sit alongside as off-chain reference points so you can see how the contract translates across regulatory and settlement regimes.
Resolution & payout
Settlement is on-chain via UMA Optimistic Oracle. A proposer posts the outcome with a bond, a two-hour dispute window opens, then the smart contract lifts winning conditional tokens to 1 USDC and sends payments to holders' wallets automatically. No withdrawal fees beyond Polygon gas.
Off-chain venues (Kalshi, Betfair, Smarkets) settle in local fiat through bank-side clearing — faster than SWIFT, slower than on-chain. Manifold pays no real cash.
FAQ
- What does a transaction cost on Polygon?
- Polygon gas is typically under $0.01 per transaction. A full trade cycle (Approve + Order + Fill) totals around $0.03 — compared to $5-50 on Ethereum mainnet.
- How does UMA secure the resolution?
- The UMA Optimistic Oracle uses a bond system: a proposer posts a bond, a two-hour challenge window opens. On dispute the losing side forfeits the bond — financial incentive for honest resolution.
- How volatile are crypto prediction markets?
- Crypto markets react to spot prices — a 5% BTC move typically shifts a "BTC above X by date" market 10-20%. Polymarket crypto market liquidity is usually six-figure USD, sufficient for active trading.
- Which crypto markets exist on Polymarket?
- Currently active markets include BTC/ETH/SOL price targets, halving dates, ETF approvals, hard-fork outcomes and Layer-2 TVL thresholds. The list updates weekly; biggest volume sits on BTC and ETH price forecasts.
- Are crypto prediction markets taxable in the US?
- In the US, prediction market gains are typically treated as ordinary income or short-term capital gains depending on holding period. Consult a tax professional for your specific situation — we cannot provide tax advice.
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