Highest temperature in Guangzhou on July 31?

Platform comparison

Market context

The real-world event is whether Guangzhou Baiyun International Airport logs a day’s high that lands inside a specific Celsius band on 31 July, with the market currently pricing **0% YES**. That makes the field a heavy favourite for a **NO** outcome, and the only genuine value angle is a contrarian read that the observed peak could still scrape into the relevant range if the day runs materially hotter than the median forecast.

Historically, late-July Guangzhou is a warm, humid regime rather than a clean heatwave setup: typical July highs sit around the low 30s Celsius, with averages near 33°C and frequent rain or thunderstorms, while daily highs can still reach the mid-to-upper 30s on hotter days.[2][11][16] Current forecasts for 31 July cluster around the low-to-mid 30s Celsius, with one outlook showing about 34°C and thunderstorm risk, another around 31°C, and a broader monthly forecast suggesting highs from roughly 86°F to 96°F.[1][3][6][7] On that framing, the consensus leans to a moderate-to-warm day rather than an extreme spike, which supports the market’s 0% YES as the favourite, though any upward revision in the afternoon high would be the only plausible value spot for YES.

For traders, the main catalysts are the day’s actual weather evolution, especially cloud cover, convective storms, and timing of showers, because Guangzhou’s summer highs can be clipped quickly by rainfall or built up sharply if sunshine holds through early afternoon.[2][3][16] The airport station’s reading will matter more than citywide forecasts, so late-morning and early-afternoon observation updates are the key dependency, not just headline forecasts. A contrarian angle is that humid, storm-prone conditions can produce a brief pre-thunderstorm temperature surge; the consensus still sits with a non-qualifying high, but any break towards the upper end of the forecast range would be the spot to watch.

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

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

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.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.