Highest temperature in Shanghai on August 18?

Platform comparison

Market context

Shanghai will experience peak summer heat on 18 August 2026, with the highest temperature reading at Pudong International Airport Station determining settlement. The market currently prices all temperature ranges at 0% probability on Polygon, suggesting either technical listing issues or extreme illiquidity in this contract. Traders are settling conditional tokens (YES/NO pairs) denominated in USDC, meaning the winning range will convert to full value whilst losing positions expire worthless upon resolution at the settlement window close on 18 August 2026 at 12:00 UTC.

Historical August temperatures at Shanghai Pudong show consistent patterns: the station typically records daily highs between 32–36°C during mid-August, with occasional peaks reaching 37–38°C during heat waves. The 2013 heat wave pushed readings to 40.6°C, though such extremes occur roughly once per decade. Current crowd pricing at 0% across all ranges appears disconnected from climatological norms, suggesting the market may reflect low trading volume rather than genuine forecasting consensus. Comparable weather markets on Polymarket typically show meaningful probability mass distributed across multiple temperature bands when liquidity exists.

The China Meteorological Administration publishes 10-day forecasts in early August, which will provide the first concrete guidance on whether 2026 brings typical summer conditions or anomalous heat. El Niño or La Niña patterns active in mid-2026 could shift baseline expectations; traders should monitor Pacific sea surface temperature anomalies published by NOAA in July and early August. Weather Underground's Daily Observations table—the explicit resolution source—occasionally records station readings that diverge slightly from summary displays, making direct verification against raw data essential before settlement.

Methodology

This page reviews Highest temperature in Shanghai on August 18? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Polymarket Alternative UK, which mirrors the Polymarket order book at 0% fees.

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.

UK Frequently Asked Questions

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.

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%.