Highest temperature in Shanghai on June 30?

Platform comparison

Market context

The highest temperature recorded at Shanghai Pudong International Airport on 30 June 2026 will determine the outcome of this prediction market, with the current crowd-implied probability sitting at 32% for the "YES" resolution. Today, Polymarket prices this contract at 0.32 USDC per share on the Polygon network, reflecting a conditional token market where traders bet on whether the peak temperature will exceed a specific threshold. The settlement window closes at 12:00 UTC on 30 June 2026, with Wunderground serving as the definitive resolution source for the daily high.

Historical data frames this probability against typical June conditions where daily highs at Pudong rise from 77°F to 83°F, rarely exceeding 92°F or falling below 69°F[1]. The hot season officially begins on 17 June, with average daily highs consistently surpassing 80°F through mid-September[6]. Recent forecasts for June 2026 indicate daily highs ranging between 80°F and 85°F, suggesting the 32% probability aligns with the upper edge of normal variability rather than an extreme outlier[7]. Summer climates in Shanghai regularly exceed 30°C, reaching 35°C during the most sunny periods[5].

Traders should monitor the hourly wind speed, which remains constant at approximately 11.3 mph throughout June, as sustained high winds can suppress peak temperatures[1]. Humidity levels are also critical, with current forecasts showing 84% humidity that could influence heat retention and the final recorded high[2]. The primary catalyst is the real-time weather update for Tuesday 30 June, where the forecast predicts a high of 27°C (80°F), which traders must weigh against the possibility of a sudden heat spike[2]. No major weather announcements are scheduled, making the on-chain price action dependent on the live Wunderground feed as the settlement clock ticks down.

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

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

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.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

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.