Highest temperature in Shenzhen on July 17?

Platform comparison

Market context

Shenzhen’s Bao’an International Airport will record its peak temperature for 17 July 2026, with the market resolving to the Celsius range containing that value. The crowd currently assigns a 0% probability to the YES outcome, implying near-certainty that the temperature will fall outside the specific range being traded, though Polymarket data shows the frontrunner outcome is 27°C at 70% probability, with 28°C at 21% [1]. This divergence suggests the 0% figure may reflect a misaligned binary contract or a specific threshold not met by the leading temperature forecasts.

Historical July weather in Shenzhen is consistently hot and humid, with average daily highs reaching 31.1°C and monthly averages around 32°C [2][3]. Rainfall is significant, averaging 211.2mm to 340mm across roughly 7 to 17 rainy days, often influenced by the subtropical high and typhoon activity [2][3]. Given these norms, a peak of 27°C or 28°C would be unusually cool for mid-July, making the 70% probability on 27°C appear statistically conservative unless a major cooling event is forecast.

Traders should monitor real-time updates from Wunderground, the designated resolution source, for the Bao’an station’s daily maximum [1]. Key catalysts include typhoon warnings or heavy rain forecasts from the Guangdong Meteorological Bureau, which could suppress temperatures below the typical 31–32°C range [3]. No recent news announcements specifically alter the July 17 outlook, but the high humidity and precipitation frequency remain the primary dependencies for a cooler-than-average peak [2][3].

Sources: 1 · 2 · 3

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

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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 Best Prediction Markets 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.