Highest temperature in Guangzhou on July 20?

Platform comparison

Market context

Guangzhou will experience its peak summer heat on 20 July 2026, with the highest temperature recorded at Baiyun International Airport determining the outcome of this weather contract. The crowd-implied probability of a YES outcome sits at 0%, suggesting traders believe the temperature will fall outside the specific range offered, though no alternative range is detailed in the market description to confirm the exact threshold being rejected.

Historical data from previous July periods shows Guangzhou Baiyun Airport routinely records maximums between 32°C and 36°C, with extreme heatwaves occasionally pushing readings to 38°C or higher. In comparable years, such as 2022 and 2023, the city faced sustained high-pressure systems that drove temperatures into the mid-30s, making a 0% probability for any plausible range statistically anomalous unless the range is set unrealistically low or high. This divergence between historical norms and current pricing warrants scrutiny when comparing odds against platforms like Kalshi, where similar weather contracts often reflect more conservative probability distributions.

Traders should monitor the China Meteorological Administration’s daily forecasts for the Pearl River Delta, particularly any updates on the subtropical ridge position and incoming tropical disturbances expected to influence southern China this week. A recent report from the South China Morning Post noted that July 2026 has seen elevated humidity levels across Guangdong, which could amplify heat stress even if air temperatures remain moderate. With the settlement window closing at 12:00 UTC on 20 July, real-time Wunderground data for ZGGG will be the sole resolution source, meaning any delay in official reporting could create temporary pricing inefficiencies across prediction markets.

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.

FAQ

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 PolyGram. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

Do I need to KYC for this market?

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

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.