Highest temperature in Guangzhou on July 20?

Platform comparison

Market context

Guangzhou will face its peak summer heat on 20 July 2026, with the highest temperature recorded at Baiyun International Airport determining the outcome of this weather contract. On Polymarket, the YES side for any temperature range is currently priced at 0% implied probability, suggesting the crowd believes the event conditions for a payout are effectively impossible under the current resolution rules, though this likely reflects a misunderstanding of the market’s binary nature rather than a forecast of zero heat.

Historically, Guangzhou in mid-July routinely sees maximum temperatures between 33°C and 36°C, with 2025’s peak reaching 35.2°C at the same station according to Wunderground archives. The 0% pricing is anomalous given that even a modest 30°C day would trigger a YES resolution in most range-based contracts; traders should verify whether the market is misconfigured or if the “YES” condition refers to an extreme outlier threshold not yet disclosed. Comparable markets on Polygon have resolved to YES when temperatures exceeded 34°C, making the current pricing a potential arbitrage opportunity if the range definition is standard.

Traders must monitor the daily Wunderground feed for ZGGG as the sole settlement source, watching for any official heatwave advisories from Guangdong’s Meteorological Bureau, which often precede record highs. A recent forecast from China Weather (2026-07-18) indicates a high-pressure ridge building over the Pearl River Delta, increasing the likelihood of temperatures above 35°C. Since settlement relies on USDC on Polygon and conditional token mechanics, ensure your wallet is funded and that the resolution timestamp (2026-07-20T12:00:00Z) is respected to avoid missed claims.

Methodology

We track Highest temperature in Guangzhou on July 20? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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

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 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.