Highest temperature in Guangzhou on August 4?

Platform comparison

Market context

Guangzhou Baiyun Airport is the reference point here, so the key variable is the **day’s peak reading at that station** on 4 August rather than the citywide average. In late summer Guangzhou is normally hot, humid and rain-prone: forecasts for early August put the city around **32–33°C at the top end**, with official regional guidance calling for Guangzhou to reach **32°C** on the day and other local weather guides clustering August highs in the **low-30s Celsius**. That makes the market a useful test of whether the airport station posts a routine hot-day maximum, or whether cloud, rain and convection cap the afternoon spike below the upper buckets. [1][2][3][15][18]

For a programme-driven approach, the practical edge is in mapping the station feed to the settlement bands and watching whether the noon-to-mid-afternoon window ever breaks through the next bracket before the 12:00Z cutoff. Crowd pricing at **0% YES** implies the market is not currently assigning value to an outcome in the defined “YES” range, so a trader would usually check whether that reflects a wording mismatch, a stale book, or a genuine expectation that the maximum will land outside the trigger band. Comparable August climatology suggests the airport often sits near **33–35°C** on hotter days, but cloudburst-style rain can flatten intraday highs quickly in Guangzhou’s monsoon season. [10][14][17][18]

The main catalysts are local convection, thunderstorm timing and any shift in the Guangdong forecast issued by the Guangzhou meteorological authorities, which today called for **moderate rain becoming overcast** in Guangzhou with a **25–32°C** range. That matters because a morning rain shield can suppress the eventual maximum, while any late clearing can still leave enough time for a short-lived spike before the settlement window ends. A bot or conditional-order workflow would typically watch successive forecast refreshes, the airport observation stream, and the actual daily maximum published by Wunderground for Guangzhou Baiyun International Airport, then compare that realised value against the market’s bands. [2][8][16]

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

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.