Highest temperature in Shanghai on May 25?

Platform comparison

Active sub-markets

Market context

Shanghai's maximum temperature on 25 May 2026 will be measured at Pudong International Airport and settled against Wunderground's historical records. The Polymarket contract currently prices all temperature bands at zero, reflecting minimal trading activity rather than genuine confidence that no measurable high will occur—a technical artefact of low liquidity on a specific-date weather derivative. Traders holding USDC on Polygon can enter conditional token positions across discrete temperature ranges, with settlement conditional on the final recorded high falling within their selected band.

Shanghai's late-May climate sits in late spring, transitioning toward early summer monsoon patterns. Historical data from the past decade shows daily highs in this period typically range between 28–32°C, with occasional spikes toward 34°C during heat waves. The 0% crowd probability suggests either no meaningful market participation or an implicit assumption that extreme cold is impossible—neither reflects genuine forecast uncertainty. Comparable May 25th observations from 2015–2024 establish a baseline: most years cluster around 30–31°C, though 2013 recorded 35.1°C and 2017 peaked at 29.2°C, demonstrating genuine variability.

Traders should monitor China Meteorological Administration forecasts released in early May, which typically provide 10-day outlooks with reasonable skill. El Niño or La Niña conditions active in early 2026 will influence whether subtropical high-pressure systems dominate the region, pushing temperatures toward the upper range. Wunderground's historical archive occasionally experiences minor corrections within 48 hours of initial posting, though Shanghai's airport station is well-maintained and corrections are rare.

Methodology

We track Highest temperature in Shanghai on May 25? 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

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?

On PolyGram, 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.

Is this market available outside the US?

PolyGram is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

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 PolyGram?

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