Highest temperature in Shanghai on June 20?

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Market context

Shanghai Pudong International Airport is set for a warm June day, but the key market variable is the *single highest reading* logged on Wunderground at the station before the settlement cut-off, not the citywide afternoon forecast. Current forecasts around the airport point to a sunny or partly cloudy spell with temperatures around 65°F to the low 80s°F in some models, which is roughly the mid-20s°C to high-20s°C range[1][5][8]. For a temperature market, that matters because the top print can come from a brief warming window rather than the headline high shown by a broad weather app.

Historically, Shanghai Pudong’s June climate supports warm outcomes: WeatherSpark says average daily highs in June at the airport rise from about 77°F to 83°F, with highs rarely falling below 69°F or exceeding 92°F[3], and its broader climate page says the hot season begins around 17 June[7]. That framing helps explain why a 0% implied YES price is unusual if the market’s YES band covers a warm threshold, although the exact interpretation depends on the contract’s temperature ranges. On platforms, Polymarket and similar crypto-native books tend to express the price directly as an implied probability, whereas Betfair and Smarkets typically show decimal prices/odds and deduct commission from winnings; in practice, the same forecast can look cheaper or more expensive once fees, spreads, and conversion between probability and odds are applied.

Traders should watch for last-minute changes in the airport forecast, especially cloud cover, rain bands, and wind shifts, because those can cap the day’s peak temperature even when the broader week looks hot[1][8]. The settlement source is Wunderground’s daily history for Shanghai Pudong International Airport, so the relevant catalyst is not a city bulletin but the final observed maximum at that station before the window closes[4]. KYC reach also differs: Polymarket access is more restricted by jurisdiction and on-chain onboarding, while Betfair and Smarkets generally require standard identity verification and are available in a narrower set of regulated markets.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in Shanghai on June 20? specifically across Polymarket, Kalshi, Betfair Exchange and Smarkets. Live odds come from the Polymarket order book; the other venues' contract details are maintained manually because their APIs aren't directly comparable. Every CTA routes to Polymarket Alternative, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Settlement is the biggest difference between the four platforms: Polymarket on-chain in USDC (instant), Kalshi USD via CFTC (T+1), Betfair and Smarkets in local currency via bank withdrawal (T+1 to T+3). Polymarket Alternative routes every trade directly into Polymarket's on-chain settlement, which is why payouts land fastest.

FAQ

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 Alternative?

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

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within 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.