Highest temperature in Shenzhen on August 9?

Platform comparison

Market context

Shenzhen’s peak temperature will be measured at Bao’an International Airport and settled from Weather Underground’s *Daily Observations* table, not the summary high/low box. That distinction matters because the current crowd price already leans to the low end of the usual August range: Polymarket shows **36°C** as the leading outcome at 54%, with **37°C** next at 32%, while broader forecast sites are clustered around the mid-30s Celsius rather than the upper-30s.[5][9][14][16]

The historical frame is straightforward: late-summer Shenzhen is hot, humid and often near the low-to-mid 30s Celsius, with August normals commonly cited around 32–34°C and frequent cloud cover or thunderstorms limiting extreme highs.[10][17][19] Current guidance from AccuWeather and similar forecast services points to roughly **35–36°C** today, which sits close to the dominant market band and suggests that a 36°C settlement is more consistent with consensus than the market’s 0% YES reading implies.[2][9][18] On that basis, the contract looks mispriced versus both the public forecast stack and the prediction-market crowd.

The main catalysts are the day’s observation updates themselves: traders should watch for the hourly progression at Shenzhen Bao’an Airport and any late-afternoon heat spike before the first datapoint for the following date is published, because Polymarket says revisions within the market window count only until that cut-off.[5] In practical terms, the key dependency is whether cloud cover, rain or onshore flow caps the airport reading in the mid-30s or allows a brief push higher; no separate policy, schedule or announcement risk is likely to matter as much as the station data.[3][4][8]

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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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'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.

Do I need to KYC for this market?

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