Highest temperature in Beijing on July 21?

Platform comparison

Market context

Beijing's peak temperature on 21 July 2026 will be measured at Capital International Airport Station and resolved against historical weather data. The current 0% probability assigned to this market reflects the settlement window closing at midday UTC, meaning traders are pricing in that the highest temperature reading will fall outside whichever range this market's upper bound represents. July in Beijing typically sees daily highs between 29–34°C, with occasional peaks above 35°C during heat waves, so the resolution hinges entirely on which specific temperature bracket the market offers and whether that bracket sits above or below the seasonal norm for that date.

Historical July records at Beijing Capital International Airport show extreme variability. The station recorded 41.9°C on 20 July 1992 during a notable heat event, whilst more recent Julys have produced highs in the 32–36°C range. The 0% crowd probability suggests traders believe the settlement range is pitched above the realistic maximum for that particular day in 2026, or the market structure itself creates a mismatch between available outcomes and expected conditions. Without visibility of the specific temperature brackets offered, the probability reflects either an implausibly high threshold or a technical settlement constraint.

Traders monitoring this market should track China Meteorological Administration forecasts released in early July 2026, which typically provide 10-day outlooks for Beijing. Atmospheric pressure patterns and any monsoon activity in the preceding weeks will signal whether heat-wave conditions are likely. Wunderground's historical database will be the definitive source, so any discrepancies between preliminary reports and the final airport station reading could affect settlement interpretation.

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 Prediction Today. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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 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.