Highest temperature in Shanghai on June 30?

Platform comparison

Market context

The real-world event hinges on the peak temperature recorded at Shanghai Pudong International Airport on 30 June 2026, measured in degrees Celsius and resolved via Wunderground data. Historically, June in Shanghai sees daily highs climb from roughly 25°C to 28°C, rarely dipping below 21°C or exceeding 33°C, with the hot season formally beginning mid-June [1][6]. Summer peaks regularly surpass 30°C, occasionally reaching 35°C under intense sun [5]. Given this baseline, a 31% crowd-implied probability for a specific high-temperature range suggests the market is pricing in a near-average day rather than an extreme heatwave, aligning with typical late-June variability where temperatures hover near the 27–28°C mark [2].

Traders approaching this programmatically should monitor real-time weather feeds for sudden shifts in cloud cover, humidity, or wind speed, as these directly modulate peak temperatures. A key catalyst is the forecasted rain and thunderstorm risk for 30 June, which could suppress highs below 27°C if precipitation occurs [2][7]. Conditional orders might be triggered by Wunderground’s hourly updates, particularly if the 14:00–16:00 window shows temperatures stalling below 26°C. Recent 14-day forecasts indicate a 25% thunderstorm risk and light rain on 29 June, with rain continuing into 30 June, suggesting a cooler, cloudier day that may invalidate higher-temperature bets [7]. Programmatic strategies should weight these dependencies heavily, using API-driven alerts to adjust positions before the settlement window closes at 12:00 UTC on 30 June.

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.

FAQ

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Polymarket App UK. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

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?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Polymarket App UK trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.