Highest temperature in Shanghai on June 30?

Platform comparison

Market context

The real-world event in question is the highest temperature recorded at Shanghai Pudong International Airport on 30 June 2026, measured in degrees Celsius and resolved via Wunderground data. Historical patterns for this location show daily highs in June rising from 77°F to 83°F, rarely dipping below 69°F or exceeding 92°F, with the hot season officially beginning around 17 June when averages surpass 80°F [1][6]. Summer highs regularly exceed 30°C (86°F), reaching 35°C (95°F) under peak sunny conditions, which frames the current 31% YES probability as a moderate bet on temperatures landing in a higher bracket rather than an outlier event [5].

A power-user approaching this market programmatically would monitor real-time weather feeds from Wunderground and cross-reference with BBC’s day-by-day forecast, which currently predicts a high of 27°C (80°F) for 30 June with 84% humidity and steady pressure at 1011mb [2]. Key catalysts include sudden shifts in shortwave solar energy, which is gradually decreasing through June, and wind speed, which remains constant near 11.3 mph, both influencing peak temperature outcomes [1]. Traders should also track any unannounced heatwave advisories or local meteorological updates, as these dependencies can rapidly alter settlement values within the final hours before the 2026-06-30T12:00:00Z deadline.

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 Kalshi Fees. 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 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.

Do I need to KYC for this market?

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