Highest temperature in Shanghai on August 10?

Platform comparison

Market context

The real-world event is whether Shanghai Pudong International Airport records a **highest temperature** that falls into the market’s specified Celsius band on 10 August 2026. In prediction markets, a **YES** share pays out if that outcome happens and a **NO** share pays out if it does not, so the key question here is not what the app headline says but what Weather Underground’s **Daily Observations** table shows for the station on the day. [7]

For context, Shanghai in August is typically hot and humid, with average highs around the low-30s Celsius and frequent rain or thunderstorms, which means daily peak temperatures can swing sharply depending on cloud cover and convection. Weather history sources for Shanghai show August highs commonly near 32–35°C, while station-based records on Weather Underground list a much higher all-time high, illustrating that even a modest-looking daily forecast can still leave room for an upper-band result if conditions clear briefly. [5][6][7][14][15]

For traders, the main catalysts are the actual hourly observations around the settlement window, plus any late-day rain, thunderstorm, or sea-breeze effects that can cap the day’s maximum temperature. At 1 am UTC, public forecasts for Shanghai already pointed to very warm, unsettled conditions, with rain or thunderstorms mentioned in extended forecasts and recent history showing heavy rain in the days before, so the market is ultimately about the intraday peak rather than the morning starting point. [1][9][13]

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.

UK Frequently Asked Questions

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 Prediction Market 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.

Is Polymarket legal in the UK?

Polymarket is accessible to UK traders but is not UKGC-licensed. It operates under US CFTC jurisdiction. UK residents face no domestic legal prohibition on using it, but UKGC consumer protections do not apply. For UKGC-regulated alternatives, Betfair Exchange and Smarkets offer similar prediction-style markets.

Do I pay tax on prediction market profits in the UK?

UKGC-licensed platform profits (Betfair, Smarkets) are typically tax-free gambling winnings for UK individuals. Polymarket profits involve USDC crypto transactions, which HMRC treats as Capital Gains Tax events. Keep full transaction records and report via Self Assessment if gains exceed £3,000 per tax year.

How do I deposit on Polymarket from the UK?

UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.