Highest temperature in Guangzhou on August 15?

Platform comparison

Market context

On 15 August 2026, the highest temperature recorded at Guangzhou Baiyun International Airport will determine this market's resolution, with measurements sourced from Weather Underground's Daily Observations table rather than summary figures. The current crowd-implied probability of 0% suggests traders are pricing in either an exceptionally low temperature threshold or uncertainty about the specific range boundaries in play.

Guangzhou's August climate presents a consistent baseline for comparison. Historical data from the past decade shows daily highs in mid-August typically range between 32–36°C, with occasional peaks above 37°C during heat waves. The 0% probability across prediction markets indicates the market may be calibrated to a temperature range well above typical August conditions, or settlement mechanics around the specific threshold have created pricing anomalies. Kalshi and Polymarket show no meaningful divergence on this contract, both reflecting the same compressed odds, suggesting consensus rather than cross-platform arbitrage opportunity.

Traders should monitor China Meteorological Administration forecasts released in early August 2026, particularly any alerts for heat waves or tropical systems affecting southern China. The South China Sea typhoon season peaks in August and September; any tropical cyclone activity could suppress temperatures significantly below the historical August norm. Additionally, the precise temperature range boundaries—which determine whether outcomes cluster at 33–35°C versus 36–38°C—will become critical as settlement approaches, since Weather Underground's Daily Observations table occasionally records fractional temperatures that could shift resolution between adjacent ranges.

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.

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.