Highest temperature in Guangzhou on July 4?

Platform comparison

Market context

On 4 July 2026, the highest temperature recorded at Guangzhou Baiyun International Airport will determine the outcome of a Polymarket contract priced at 0% YES for a 31°C threshold. This on-chain market, settled in USDC on Polygon via conditional tokens, reflects a crowd-implied certainty that the day will not reach that heat, despite Guangzhou’s reputation for extreme summer conditions.

Historically, July is Guangzhou’s hottest month, with average highs around 33°C (91°F) and daily peaks rarely falling below 85°F or exceeding 96°F[1][4]. AccuWeather’s 2026 forecast for July shows highs ranging from 87°F to 100°F, suggesting that 31°C (87.8°F) is actually a conservative benchmark[2]. The current 0% probability appears misaligned with climatology, though monsoon positioning may be tempering expectations[5].

Traders should monitor real-time weather updates from Wunderground and any official announcements on regional heat advisories or monsoon shifts. Recent reports note Guangzhou experiencing its longest summer since 1961, with record summer-day counts and sustained high temperatures[6]. Reddit users also describe “insane heat” with temperatures consistently over 30°C, reinforcing the likelihood of a hotter-than-expected outcome[7]. The Met Office forecasts an 80% chance of rain and maximum feels-like temperatures of 32°C, which could influence the final reading[8].

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

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 Polymarket Legit?. 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.

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 Polymarket Legit? trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.