Highest temperature in Shanghai on August 21?

Platform comparison

Market context

Shanghai's weather on 21 August 2026 will depend heavily on the intensity and track of any tropical systems affecting East China during late summer. The 0% crowd probability suggests traders are either awaiting clearer meteorological guidance or treating this as a placeholder market pending seasonal forecasts. Over the past 48 hours, no significant weather alerts or model shifts have emerged for that specific date, leaving the market in a holding pattern until mid-summer forecasting becomes more reliable.

Historical August temperatures at Shanghai Pudong International Airport typically peak between 32–35°C, with occasional extremes reaching 36–37°C during particularly intense heat waves or when typhoon remnants stall over the region. The 2013 heat wave pushed readings to 38.3°C, whilst more recent years have seen peaks in the 34–36°C range. These precedents matter because they establish the plausible upper bounds; any resolution above 37°C would require either an exceptional heat event or unusual atmospheric conditions, which current long-range models do not suggest.

Traders should monitor the Asian summer monsoon progression and tropical cyclone activity in the Western Pacific from June onwards, as these directly influence August conditions. China Meteorological Administration seasonal outlooks, typically released in May and updated monthly, will provide the first substantive guidance on whether August 2026 leans towards above or below-normal temperatures. Additionally, any El Niño or La Niña signals emerging in the coming months could shift regional pressure patterns and thus the likelihood of extreme heat.

Methodology

This page reviews Highest temperature in Shanghai on August 21? 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 Prediction Today, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

UK Frequently Asked Questions

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.

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%.