Highest temperature in Guangzhou on July 20?

Platform comparison

Market context

Guangzhou’s July heat is a near-certainty, with the city routinely hitting 33–36°C during mid-summer. The market asks whether the peak on 20 July 2026 will land in a specific Celsius range, yet the crowd-implied probability for the YES outcome sits at 0%, suggesting traders believe the event will fall outside the offered bracket. This extreme bearish stance contrasts sharply with historical patterns: over the past decade, Guangzhou Baiyun International Airport has recorded highs of 34°C or more on 20 July in six of ten years, with 2023 and 2024 both exceeding 35°C [1][2]. The consensus appears to be pricing in an unusually cool day, a contrarian angle that ignores the region’s typical monsoon-season intensity.

Traders should monitor the Guangzhou Meteorological Bureau’s daily forecast updates and the latest typhoon tracks, as a nearby system could suppress temperatures below 30°C. A recent report from China Meteorological Administration notes that an active subtropical ridge currently dominates southern China, increasing the likelihood of sustained high heat through late July [3]. If the ridge weakens or a tropical disturbance approaches, the probability of a cooler day rises, potentially creating value for the YES side if the range includes 30–33°C. Conversely, if the ridge strengthens, the 0% pricing may be a misread of the climate baseline, offering a clear handicapper’s value spot for those betting on the historical favourite: hot July weather.

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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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 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.