Highest temperature in Shenzhen on August 21?

Platform comparison

Market context

On 21 August 2026, the highest temperature recorded at Shenzhen Bao'an International Airport will determine this market's resolution. The contract currently trades at 0% implied probability across all temperature bands, suggesting either extreme uncertainty about which range will settle or a technical pricing anomaly. Polymarket's conditional token architecture means traders are purchasing USDC-denominated positions on Polygon, with payouts determined by Weather Underground's Daily Observations table—a specification that matters because discrepancies sometimes emerge between that granular dataset and the summary "Day High & Low" figures displayed elsewhere.

Shenzhen's August climate is remarkably consistent. Historical data from the past decade shows daily highs clustering between 32–35°C during mid-August, with occasional spikes to 36–37°C during heat waves. The city's coastal subtropical location and urban heat island effects create narrow variance; temperatures below 31°C or above 38°C on this date would constitute statistical outliers. The 0% crowd probability across all ranges suggests the market may lack sufficient liquidity or trader participation to generate meaningful price discovery, rather than reflecting genuine consensus that no temperature will be recorded.

Traders should monitor China's meteorological forecasts released in early August 2026, particularly alerts from the China Meteorological Administration regarding typhoon activity or heat dome formation. Tropical systems occasionally affect Guangdong Province in late summer, potentially depressing temperatures, whilst persistent high-pressure systems can drive readings into the upper 30s. Weather Underground's data feed reliability—occasionally subject to station maintenance or reporting delays—represents the only resolution dependency that matters operationally.

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

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

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 Polymarket Scam?. 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%.