Highest temperature in Shenzhen on August 20?

Platform comparison

Market context

On 20 August 2026, the highest temperature recorded at Shenzhen Bao'an International Airport will determine the settlement of this contract. The market currently shows 0% implied probability across the crowd, suggesting either extreme confidence in a specific temperature band or insufficient trading activity to establish meaningful odds. Resolution will depend on the Daily Observations table from Weather Underground rather than summary figures, a distinction that occasionally produces discrepancies in historical weather data reporting.

Shenzhen's August climate is consistently hot and humid, with daily highs typically ranging between 32–35°C during the peak summer season. Historical records from the airport station show that temperatures exceeding 36°C occur in roughly 15–20% of August days, whilst readings above 38°C are rare but not unprecedented. The 0% crowd probability suggests traders may be anchored to a narrow range, or the market lacks sufficient liquidity to reflect genuine uncertainty across multiple temperature bands. Comparable prediction markets on regional temperature extremes often show wider probability distributions once trading volume increases.

Weather forecasting accuracy for specific daily highs degrades significantly beyond ten days, making early-August 2026 predictions unreliable. Traders should monitor tropical cyclone activity in the South China Sea during late July and early August, as storm systems can suppress temperatures substantially. The China Meteorological Administration's seasonal outlooks and any official heat-wave warnings issued in early August will provide the most actionable signals for reassessing the current flat probability distribution.

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

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

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 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.