Highest temperature in Shanghai on June 21?

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Market context

Polymarket is pricing this Shanghai temperature contract at **0% YES** for the moment, so the market is effectively assigning no weight to the Pudong Airport station printing into the relevant temperature band for 21 June. On Polymarket, traders buy and sell **USDC-settled conditional tokens** on Polygon, so the live price is a direct read on where marginal liquidity thinks the day’s highest recorded temperature will land at the Wunderground resolution point.

For context, late-June Shanghai is normally in the hot season, and Pudong’s June averages are already in the low 30s °C for daily highs, with summer readings regularly moving above 30°C on warm days.[3][7] That said, the current weather picture looks mixed rather than extreme: Meteoblue’s forecast for Shanghai Pudong International Airport calls for a sunny day with highs around 65°F, alongside moderate winds and gusts up to 23 mph.[1] If that forecast verifies, it points to a materially cooler outcome than the climatological June baseline, which helps explain why a sub-expected range outcome can dominate pricing even before the daily high is finalised.

The main catalysts are the airport station’s actual afternoon heating curve, cloud cover, and any rain or thunder near Shanghai’s coastal metro area, because the market settles on the *highest* temperature recorded in Celsius at Shanghai Pudong International Airport Station on the day, not the citywide average.[1][3] Traders should watch intraday updates from weather models and airport-adjacent forecasts, plus any sharp revisions after the morning hours, because a late warm-up can still move the observed maximum even when early readings look subdued.[1][5]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Shanghai on June 21? on the five venues with material liquidity for prediction markets. Live odds come from the Polymarket Polygon order book — the only source that ships real-time data under an open licence. For Kalshi, Betfair and Manifold we list platform attributes (fee, KYC, settlement, payment) instead of fabricated odds, because their APIs use non-comparable contract definitions.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

Where can I trade this market with the lowest fees?

On Polymarket Legit?, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

Do I need to KYC for this market?

Not under $1,500 of lifetime trading volume. Above that threshold, Polymarket Legit? triggers a quick verification flow that finishes in minutes.

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.