Highest temperature in Guangzhou on August 14?

Platform comparison

Market context

On 14 August 2026, the highest temperature recorded at Guangzhou Baiyun International Airport will determine this market's settlement. The contract currently trades at 0% on Polymarket, indicating traders assess an extremely low probability for the upper temperature bands. Resolution hinges on the Daily Observations table from Weather Underground rather than the Day High & Low summary section—a distinction that matters when intraday spikes occur that don't reflect the official daily maximum.

Guangzhou's August climate provides historical context. The city experiences peak summer heat during this period, with average daily highs around 33–34°C and frequent readings exceeding 35°C. The 0% pricing suggests the market has priced in expectations well below historical norms, or traders are heavily concentrated in lower temperature bands. August 2025 saw Guangzhou record a high of 36.8°C on the 14th; comparable years show consistent patterns of mid-to-high 30s Celsius. The extreme confidence in lower outcomes warrants scrutiny of what specific temperature threshold this market's bands represent.

Traders should monitor China Meteorological Administration forecasts released in early August 2026, which typically provide 10-day outlooks with reasonable accuracy. Tropical cyclone activity in the South China Sea could suppress temperatures through cloud cover and precipitation, whilst high-pressure systems would drive readings upward. The settlement window closes at midday UTC on 14 August, creating a tight window for final observations. Weather Underground's data feed occasionally experiences delays, so traders tracking real-time airport observations will have an advantage in assessing which band the final reading will occupy.

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

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%.