Highest temperature in Shenzhen on July 20?

Platform comparison

Market context

Shenzhen will experience its peak daily heat on 20 July 2026 at the Bao’an International Airport station, a metric tracked by Wunderground to settle this weather contract. The event is a straightforward meteorological observation: the highest Celsius reading recorded anywhere between midnight and midnight local time on that specific date.

Historical data for mid-July in Shenzhen consistently shows maximum temperatures between 33°C and 36°C, with the 0% crowd-implied probability for a “YES” outcome suggesting the market currently prices an extreme outlier or a specific threshold breach as impossible. Programmatic traders would typically back-test five years of ZGSZ station data to establish a baseline distribution, noting that temperatures exceeding 37°C are rare but not unprecedented in this humid subtropical zone. The current pricing implies the market expects a standard summer day rather than a record-breaking heatwave, aligning with typical seasonal averages for the Pearl River Delta.

Traders monitoring this market should watch real-time weather feeds from the China Meteorological Administration and Wunderground’s hourly updates as the settlement window closes. No specific policy announcements or economic schedules drive this outcome; the sole dependency is atmospheric conditions, including humidity levels and cloud cover, which modulate peak heating. A sudden shift in monsoon patterns or an unexpected heat dome could alter the trajectory, but current forecasts for late July 2026 remain within normal seasonal bounds, offering no immediate catalyst for a probability spike.

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

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 Polymarket Bot UK trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

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.