Highest temperature in Shanghai on August 18?

Platform comparison

Market context

Shanghai will experience summer conditions on 18 August 2026, with the settlement contingent on the highest temperature recorded at Pudong International Airport's meteorological station. The market currently shows zero implied probability across platforms, suggesting traders view the outcome as either extremely unlikely or the market lacks sufficient liquidity to establish a meaningful line. Resolution will depend on Weather Underground's Daily Observations table rather than summary figures, a distinction that matters when station equipment records micro-variations throughout the day.

August temperatures in Shanghai typically range between 28–35°C, with occasional peaks above 36°C during heat waves. Historical data from the past decade shows that extreme heat events—those pushing above 38°C—occur roughly once every two to three years in mid-August. The current zero probability implies the market is pricing in either a cooler-than-normal August or reflects sparse trading activity rather than genuine conviction that temperatures will remain below the lowest resolution threshold. Cross-platform comparison would reveal whether sportsbooks or alternative prediction venues show divergent odds; the absence of visible probability suggests this contract may lack sufficient volume to attract mainstream weather traders.

Traders should monitor China Meteorological Administration forecasts released in early August 2026, which typically provide ten-day outlooks with reasonable accuracy for Shanghai. Pacific typhoon activity and the East Asian summer monsoon pattern will be the primary catalysts affecting temperature outcomes. Any tropical systems approaching the region in mid-August could suppress daytime highs, whilst high-pressure systems centred over eastern China would favour above-average heat. Real-time updates from Pudong station itself become critical in the final 48 hours before settlement.

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

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Kalshi vs Polymarket. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

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 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.