Highest temperature in Guangzhou on July 7?

Platform comparison

Market context

Guangzhou’s highest temperature on 7 July 2026 will be recorded at the Baiyun International Airport Station and resolved via Wunderground’s daily history, with the market currently pricing any specific outcome at 0% YES despite July being the city’s hottest month. Historical data shows daily highs in July typically cluster around 32–33°C, rarely dipping below 29°C or exceeding 36°C, with the all-time record hitting 39°C on 25 July 2024[5][7]. The 0% crowd-implied probability likely reflects a misalignment between the market’s binary framing and the continuous nature of temperature outcomes, or a technical glitch, as comparable July 3 markets showed non-zero pricing for specific bands like 34°C[1].

Traders should monitor real-time Wunderground feeds for the Baiyun station and cross-reference with Guangzhou’s seasonal heatwave patterns, which have intensified since the 1960s with extreme hot days (above 33°C) doubling in frequency[2]. Recent reports confirm China experienced its hottest July on record in 2024, with average temperatures reaching 23.2°C nationwide and Guangzhou seeing its longest summer since 1961[4][8]. Programmatically, a robust bot would ingest hourly Wunderground updates, apply a rolling maximum filter, and trigger conditional orders only once the daily high stabilises above 30°C, avoiding premature entries given the 12:00 UTC settlement window. The key dependency is the station’s data integrity; any gap in Wunderground’s hourly log could delay resolution or invalidate the market’s outcome.

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

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

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.

Do I need to KYC for this market?

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