Platform comparison
| Platform | YES odds | NO odds | Fee | KYC | Settlement | |
|---|---|---|---|---|---|---|
Polymarket (via PolyGram) Pick polygram.ink (preferred broker) |
99% | 1% | 0% (USDC on-chain) | No-KYC up to $1,500 | USDC, auto via UMA oracle | Open the market → |
Polymarket (direct) polymarket.com |
99% | 1% | 0% | Geo-blocked in US/UK/EU | USDC, on-chain | Open the market → |
Kalshi kalshi.com |
— | — | Up to 7% per trade | US-only, KYC required | USD | Open the market → |
Betfair Exchange betfair.com |
— | — | 2-5% commission | Full KYC from first trade | GBP / EUR | Open the market → |
Manifold Markets manifold.markets |
— | — | Play-money (mana) | None — play-money | Mana (no cash-out) | Open the market → |
Outcome probabilities
Current market-implied probability for each outcome, from the live order book.
| Outcome | Probability |
|---|---|
| 32°C | 99% |
| 33°C | 2% |
| 25°C or below | 0% |
| 26°C | 0% |
| 27°C | 0% |
| 28°C | 0% |
| 29°C | 0% |
| 30°C | 0% |
| 31°C | 0% |
| 34°C | 0% |
| 35°C or higher | 0% |
Market context
Shanghai will experience peak summer heat on 20 August 2026, with the settlement hinging on the precise maximum temperature recorded at Pudong International Airport's meteorological station. The Polymarket contract currently prices this outcome at 0% across all temperature bands, suggesting traders view the event as either too distant for meaningful pricing or are awaiting clearer atmospheric forecasts. Settlement will draw from Weather Underground's Daily Observations table—the granular, station-level dataset rather than summary figures—creating a technical distinction that matters when temperatures cluster near band boundaries.
Historical August temperatures in Shanghai reveal a consistent pattern: daily highs typically range between 32–35°C during the peak summer season, with occasional spikes above 36°C during heat waves. The city's subtropical climate produces humid, oppressive conditions in mid-August, though typhoon activity can occasionally suppress temperatures. Reviewing prior years' data from Pudong station shows that extreme readings above 38°C occur roughly once per decade, whilst the 33–35°C band captures the majority of August days. This distribution provides the baseline against which current zero-probability pricing should be evaluated.
Traders monitoring this contract should track China's meteorological forecasts released in late July and early August 2026, which typically offer reliable 10–14 day outlooks. Typhoon trajectories affecting the East China Sea will be critical; systems tracking toward Shanghai can dramatically lower peak temperatures, whilst high-pressure systems stalled over the region tend to intensify heat. The China Meteorological Administration publishes seasonal outlooks and weekly updates that will inform positioning before the settlement window closes on 20 August at 12:00 UTC.
Methodology
We track Highest temperature in Shanghai on August 20? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.
Resolution & payout
At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.
On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.
FAQ
- Where can I trade this market with the lowest fees?
- Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is PolyGram. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.
- Is this market available outside the US?
- Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.
- How does resolution work?
- Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.
- What's the difference between YES and NO shares?
- A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.
- How reliable are the quoted odds?
- The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.
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