Platform comparison
| Platform | YES odds | NO odds | Fee | KYC | Settlement | |
|---|---|---|---|---|---|---|
Polymarket (via Sport Prediction) Pick polygram.ink (preferred broker) |
85% | 15% | 0% (USDC on-chain) | No-KYC up to $1,500 | USDC, auto via UMA oracle | Live odds → |
Polymarket (direct) polymarket.com |
85% | 15% | 0% | Geo-blocked in US/UK/EU | USDC, on-chain | Live odds → |
Kalshi kalshi.com |
— | — | Up to 7% per trade | US-only, KYC required | USD | Live odds → |
Betfair Exchange betfair.com |
— | — | 2-5% commission | Full KYC from first trade | GBP / EUR | Live odds → |
Manifold Markets manifold.markets |
— | — | Play-money (mana) | None — play-money | Mana (no cash-out) | Live odds → |
Outcome probabilities
Current market-implied probability for each outcome, from the live order book.
| Outcome | Probability |
|---|---|
| 31°C | 85% |
| 32°C | 12% |
| 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
Shanghai's August weather is characterised by high heat and humidity, with daytime temperatures typically ranging between 32–35°C during mid-August. The city sits in a subtropical climate zone where summer peaks coincide with the East Asian monsoon season, creating conditions that favour sustained elevated temperatures. Historical records from Shanghai Pudong International Airport—the official resolution source for this market—show that temperatures on 18 August have previously reached into the mid-30s Celsius, with occasional spikes above 36°C during particularly intense heat waves.
The 0% crowd probability reflects the market's current calibration rather than any meteorological implausibility. August 18 falls within Shanghai's hottest period, and temperature ranges in the 33–36°C band are commonplace. Comparable dates from recent years demonstrate that mid-August highs regularly exceed 34°C; the question centres on which specific range the peak will occupy, not whether substantial heat will materialise. Traders should note that the resolution mechanism specifies the Daily Observations table on Weather Underground rather than summary figures, which occasionally diverge in edge cases.
Monitoring weather forecasts from mid-August onwards will be essential, particularly any alerts regarding heat waves or unusual atmospheric patterns. The China Meteorological Administration typically issues detailed 10-day forecasts by early August. Traders should track any anomalous weather systems—tropical cyclones or unexpected cold fronts—that could suppress temperatures below seasonal norms, though such deviations remain statistically uncommon for this date and location.
Methodology
Sports-specific comparison page for Highest temperature in Shanghai on August 18?. Polymarket's live quote (Polygon order book) plus platform attributes for the three reference venues. Sports markets reward liquidity — Polymarket and Betfair are materially deeper than Kalshi or Manifold.
Resolution & payout
Sports markets typically settle on official final-whistle plus league confirmation. Polymarket uses UMA Optimistic Oracle with a source URL per contract — usually official league data feeds or ESPN/Soccerway. Two-hour dispute window, then smart-contract payout in USDC.
UK Frequently Asked Questions
- Are prediction markets better than sports betting?
- Prediction markets tend toward tighter odds than bookmakers because they use peer-to-peer exchange rather than bookmaker margin. On major matches, Polymarket quotes typically sit 2-5% closer to the true probability model than bet365 or DraftKings.
- When do sports markets resolve?
- Typically within hours of the official final whistle. Polymarket uses UMA Optimistic Oracle with source URLs pointing at official league data feeds — e.g. the Premier League for EPL markets, UEFA for Champions League, FIFA for World Cup.
- Is Polymarket legal in the UK?
- Polymarket is accessible to UK traders but is not UKGC-licensed. It operates under US CFTC jurisdiction. UK residents face no domestic legal prohibition on using it, but UKGC consumer protections do not apply. For UKGC-regulated alternatives, Betfair Exchange and Smarkets offer similar prediction-style markets.
- Do I pay tax on prediction market profits in the UK?
- UKGC-licensed platform profits (Betfair, Smarkets) are typically tax-free gambling winnings for UK individuals. Polymarket profits involve USDC crypto transactions, which HMRC treats as Capital Gains Tax events. Keep full transaction records and report via Self Assessment if gains exceed £3,000 per tax year.
- How do I deposit on Polymarket from the UK?
- UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.
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