Highest temperature in Guangzhou on August 21?

Platform comparison

Market context

Guangzhou will experience peak summer heat on 21 August 2026, with the settlement hinging on the highest temperature recorded at Baiyun International Airport's meteorological station. The market currently shows zero implied probability across the full range, suggesting either incomplete pricing or a data lag in crowd assessment. Resolution will draw exclusively from Weather Underground's Daily Observations table rather than summary figures, a distinction that occasionally produces material differences in recorded extremes.

Guangzhou's August climatology provides the essential baseline. The city's mean daily maximum in August sits around 32–33°C, with historical highs frequently reaching 35–37°C during heat waves. The 2023 summer saw multiple days exceed 38°C across southern China, whilst the 2013 heat event produced readings above 39°C in Guangzhou proper. These precedents suggest the market's zero probability across all ranges warrants scrutiny; typical August conditions would ordinarily place substantial odds on the 32–35°C and 35–38°C brackets.

Traders should monitor China Meteorological Administration forecasts released in early August 2026, which typically provide 10–14 day outlooks with reasonable skill for temperature extremes. Pacific typhoon activity during late summer can suppress peak temperatures through cloud cover and moisture, whilst high-pressure systems anchored over southern China drive sustained heat. Recent patterns show La Niña conditions favour warmer-than-normal August temperatures across the region. The settlement window closes at midday UTC on 21 August, requiring traders to account for any timezone conversion between local Guangzhou observations and the resolution timestamp.

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

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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 Best Prediction Markets UK. 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.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Best Prediction Markets UK trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

What are the best prediction markets for UK traders in 2026?

For UKGC-regulated markets: Betfair Exchange (sports, politics) and Smarkets (sports, politics, lower commission than Betfair). For broader global event prediction: Polymarket (deepest liquidity, 0% fee, USDC settlement). For US-regulated option: Kalshi (USD, limited UK payment options). Most serious UK traders use a combination of Betfair for regulated sports and Polymarket for broader markets.