Highest temperature in Guangzhou on July 9?

Platform comparison

Market context

The real-world event this market tracks is the peak temperature recorded at Guangzhou Baiyun International Airport on 9 July 2026, measured in degrees Celsius. Historical data confirms July is Guangzhou’s hottest month, with daily highs averaging 33°C and rarely dipping below 29°C or exceeding 38°C. WeatherSpark notes typical highs sit around 33°C (91°F), while AccuWeather’s July 2026 forecast projects a range of 26°C to 38°C. The current 0% crowd-implied probability for “YES” appears inconsistent with these baselines, as even conservative models place the likelihood of temperatures exceeding 30°C near certainty. Programmatic traders should treat this as a mispriced outlier, using historical volatility bands to back-test conditional orders rather than relying on the flawed crowd signal.

Key catalysts include monsoon activity and urban heat index trends, which can push temperatures above 36°C during clear-sky periods. China Educational Tours reports July highs have reached 36°C in recent years, often accompanied by cloudy, rainy intervals that temporarily suppress peaks. A recent People’s Daily post highlighted May 2026 as Guangzhou’s hottest month historically, with temperatures hitting 36.3°C amid continuous sunny days, suggesting a warming trend that may persist into July. Traders monitoring Wunderground’s hourly data should watch for sudden drops in humidity or cloud cover, which act as immediate triggers for temperature spikes. Conditional bots can be set to execute when real-time readings breach 34°C, capitalising on the lag between physical events and market resolution.

Sources: 1 · 2 · 3 · 4 · 5

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.

FAQ

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.

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.

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.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.