Platform comparison
| Platform | YES odds | NO odds | Fee | KYC | Settlement | |
|---|---|---|---|---|---|---|
Polymarket (via BTC Prediction) Pick polygram.ink (preferred broker) |
83% | 17% | 0% (USDC on-chain) | No-KYC up to $1,500 | USDC, auto via UMA oracle | Open live market → |
Polymarket (direct) polymarket.com |
83% | 17% | 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 |
|---|---|
| 31°C | 83% |
| 32°C | 19% |
| 33°C | 1% |
| 26°C or below | 0% |
| 27°C | 0% |
| 28°C | 0% |
| 29°C | 0% |
| 30°C | 0% |
| 34°C | 0% |
| 35°C | 0% |
| 36°C or higher | 0% |
Market context
On 29 June 2026, Hong Kong will record its highest daily temperature, a real-world event that directly determines the settlement of a prediction market resolved to a Celsius range. The Hong Kong Observatory has forecast above-normal temperatures for June through August 2026, citing ENSO conditions and climate models that point to sustained heat[1][5]. Historical data shows June highs typically range between 87°F and 91°F (30.6°C to 32.8°C), with the average high at 90°F (32.2°C)[2]. Recent records confirm this trend: Hong Kong hit 34.6°C on its hottest day of the year so far in late June 2026, with New Territories peaking at 37°C[3][6].
Traders should monitor the Observatory’s finalised “Daily Extract” for the “Absolute Daily Max (deg. C)” on 29 June, as the market cannot resolve until this data is published[1]. Key catalysts include any extreme heat warnings issued for the New Territories, where temperatures have previously exceeded 36°C[3][9]. While the crowd-implied probability of a “YES” outcome sits at 0%, this may reflect uncertainty about the exact resolution range rather than disbelief in high temperatures. In crypto terms, this market functions as a USDC-settled on-chain contract tied to BTC/ETH macro sentiment, where whale flows into weather-linked derivatives could shift pricing if funding rates on major exchanges signal heightened risk appetite for non-correlated assets.
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
- Why USDC and not ETH or USDT?
- USDC is the Polygon standard — audited reserves (Circle, monthly attestation), deepest order book, low gas costs. ETH volatility would distort probability quotes; USDT has thinner Polygon liquidity than USDC.
- 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 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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