Highest temperature in Shanghai on August 8?

Platform comparison

Market context

Polymarket is pricing this Shanghai temperature contract at **0% YES** right now, which means the market is effectively assuming the daily maximum at Shanghai Pudong International Airport on 8 August will land outside the YES range. On Polymarket, that view is expressed through USDC-backed trading on Polygon via conditional tokens, so the live price is the crowd’s current estimate of where the Wunderground daily-observations high will settle, not a forecast in the meteorological sense.

For context, Shanghai’s August climate is normally hot enough that a low-range outcome is not the base case: long-run summaries cluster around daytime highs in the low 30s Celsius, with several sources pointing to early-August highs near 31–35°C and humid, unsettled conditions[1][4][12][14]. That matters for reading a 0% market, because it usually reflects either a very narrow resolution band or an expectation that the day’s peak will slip just below the threshold; in a city this warm, a sub-threshold close is still plausible if rain, cloud cover, or a typhoon-related cooling pattern caps the afternoon maximum[2][3][5].

The immediate catalysts are the weather updates traders watch hour by hour: AccuWeather flags a Blue Warning for Typhoon and forecasts showers, thunderstorm risk, and a high around 93°F for 8 August, while Weather Underground shows Shanghai at 92°F with the site updated on the morning of 8 August[2][3][8]. For a hands-on Polymarket user, the key is not the headline high alone but whether the Wunderground Daily Observations table prints a maximum inside the contract’s range before the settlement window closes at 12:00 UTC, because that table controls resolution if it differs from any summary display.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

Resolution & payout

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

UK Frequently Asked Questions

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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.

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