Highest temperature in Shenzhen on May 25?

Platform comparison

Active sub-markets

Market context

Shenzhen will record a maximum daily temperature on 25 May 2026, measured at Bao'an International Airport Station. The settlement hinges on Wunderground's historical weather database, which aggregates readings across all daylight and evening hours to determine the single highest figure for that calendar date. This market structure differs notably across platforms: Polymarket presents binary ranges with decimal odds, whilst Kalshi and Betfair typically offer tighter spreads on weather contracts through their respective fee structures (Polymarket charges 2% on winnings; Kalshi's model varies by product). Smarkets' commission-based approach can favour high-volume traders on weather markets where implied probabilities shift rapidly.

May in Shenzhen falls within late spring, when subtropical conditions drive temperatures into the high 20s to low 30s Celsius. Historical data from the same station shows May 25 readings clustering between 28–32°C over recent years, though extremes have occasionally breached 34°C during particularly warm seasons. The 0% crowd probability currently assigned suggests either insufficient liquidity or traders awaiting clearer seasonal forecasts before committing capital.

Traders should monitor China Meteorological Administration seasonal outlooks released in April 2026, which typically forecast May conditions three to four weeks ahead. El Niño or La Niña patterns influence southern China's spring temperatures materially. The absence of scheduled weather events (typhoons, cold fronts) in late May historically makes this period relatively predictable compared to summer months, reducing tail-risk volatility that might otherwise compress odds across competing platforms.

Methodology

We read Highest temperature in Shenzhen on May 25? from four platform perspectives: Polymarket (on-chain CLOB), Kalshi (CFTC-regulated exchange), Betfair Exchange (sports book exchange), Smarkets (peer-to-peer betting exchange). Polymarket's live quote comes directly from the Polygon order book; the other three are listed with their platform attributes — fees, KYC, settlement currency, payment options — because a 1:1 contract comparison without API access would be guesswork.

Resolution & payout

Polymarket settles via UMA Optimistic Oracle on Polygon. A proposer posts the outcome with a bond, the two-hour window runs, then the smart contract pays USDC.

Kalshi settles USD through the CFTC-regulated clearinghouse — the cleanest variant, with heavier KYC. Betfair Exchange settles in account currency (GBP/EUR), net of 2-5% commission. Smarkets follows the same model as Betfair with a lower default 2% commission.

FAQ

Where can I trade this market with the lowest fees?

On PolyGram, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

PolyGram is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

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 it cost to trade on PolyGram?

Zero. PolyGram routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.