Highest temperature in Shenzhen on August 12?

Platform comparison

Market context

Shenzhen will experience peak summer heat on 12 August 2026, with the highest temperature of that day to be recorded at Bao'an International Airport Station and measured in degrees Celsius. The market resolves using Weather Underground's Daily Observations table—the granular, station-level dataset rather than the rounded Day High & Low summary figures. This distinction matters for traders building automated resolution checkers: the two sources occasionally diverge by 0.5–1.0°C, so any programmatic monitoring must query the correct endpoint. Settlement occurs at 12:00 UTC on the resolution date, giving traders a narrow window to verify the final reading before the market locks.

August in Shenzhen typically peaks between 32–35°C, with occasional spikes above 36°C during heat waves. Historical data from 2015–2023 shows that extreme readings (above 37°C) occur roughly once every three to four years in mid-August, usually driven by sustained high-pressure systems or tropical moisture. The current 0% crowd probability suggests either a technical issue with market creation or traders anticipating an unusually cool August—plausible given the 2024–2025 pattern of weaker summer heat in southern China. Comparable markets on daily temperature extremes typically see probability distributions cluster around historical medians, with tail events priced according to seasonal anomaly forecasts.

Traders should monitor China Meteorological Administration updates and tropical cyclone activity in the Western Pacific during late July and early August 2026. Typhoon season peaks in August, and any system tracking towards Guangdong would suppress daytime highs through cloud cover and precipitation. Conversely, a high-pressure ridge positioned over the South China Sea would drive sustained heat. Programmatic traders can automate alerts on CMA forecasts and cross-reference them against Weather Underground's forecast API to estimate probability shifts as the settlement date approaches.

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

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%.