Highest temperature in Shanghai on June 21?

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Market context

Shanghai Pudong International Airport is likely to see a warm, humid summer day, with the local forecast pointing to around 28–29°C and a chance of thundery showers, which means the market outcome should be driven by whether the day’s peak is capped in the high-20s or pushes into the low-30s. The settlement source is the Wunderground daily history for ZSPD, so the relevant variable is the single highest recorded temperature there before the window closes, not the average or the official noon reading.

For framing, June is already deep into Shanghai’s hot season: historical climate data for Pudong shows average June highs rising into the low-80s °F, with daily highs rarely exceeding the low-90s °F, while airport climate charts note that summer highs can regularly get above 30°C and sometimes into the mid-30s on the sunniest days.[3][4][7] That makes the current 0% YES price unusual only if the crowd is assuming a weather cap, but a simple programmatic approach would be to map the forecast distribution to the market’s temperature bands, then update as new runs shift the probability of a 30°C-plus print.

The main catalysts are the daytime convective forecast, cloud cover, and whether local thunderstorms are early enough to suppress the afternoon high or late enough to leave a warmer peak intact. Current airport guidance already flags cloud, some sunshine, local thunderstorms, and only moderate precipitation odds, which supports watching any short-term forecast updates rather than relying on the morning snapshot alone.[1][2] For a bot workflow, the practical trigger is each model refresh or airport observation update: if the forecast nudges from upper-20s into low-30s Celsius, the probability bands for the market’s resolution range can move quickly.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote (Polymarket), four reference venues with their key attributes, and a single execution path — every trade button routes to Polymarket Bot UK, which mirrors the Polymarket order book directly.

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 Bot UK, 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.

What does it cost to trade on Polymarket Bot UK?

Zero. Polymarket Bot UK routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

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.