Highest temperature in Shanghai on July 21?

Platform comparison

Market context

Shanghai faces its peak summer heat on 21 July 2026, with traders betting on the highest temperature recorded at Pudong International Airport. The market currently assigns 0% probability to the “YES” outcome, suggesting the crowd expects the temperature to fall outside the specific range offered, despite July typically bringing extreme warmth to the region.

Historical data for mid-July in Shanghai shows frequent highs between 33°C and 38°C, with 34°C and 33°C emerging as the front-runners on Polymarket at 46% and 39% implied probability respectively[1]. This divergence highlights a key platform difference: Polymarket displays decimal odds and implied probabilities directly, whereas Kalshi uses binary contracts with fixed payouts, and Betfair/Smarkets rely on traditional decimal odds without explicit probability labels. Fee structures also vary, with Polymarket charging lower trading fees compared to Kalshi’s higher spread, while KYC requirements are stricter on regulated US platforms like Kalshi versus Polymarket’s global access.

Traders should monitor real-time forecasts from Meteoblue, which currently predicts a maximum of 38°C with scattered clouds and possible thunderstorms later in the afternoon[2][3]. The settlement hinges on Wunderground’s official record for Pudong Airport, making local weather updates and storm developments critical catalysts. Any sudden shift in cloud cover or rainfall could drastically alter the temperature outcome, especially as the settlement window closes at 12:00 UTC on 21 July 2026.

Sources: 1 · 2 · 3

Methodology

We read Highest temperature in Shanghai on July 21? 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 mid is the canonical probability; the side-by-side columns benchmark fees, KYC, settlement currency and deposit rails so you can choose the venue that fits your jurisdiction and trade size.

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

Polymarket vs Kalshi — which is better?

Depends on your location. Kalshi is CFTC-regulated, US-only with full KYC. Polymarket is global, on-chain, no KYC up to $1,500. Polymarket has ~10x higher liquidity but higher regulatory risk.

What does Polymarket cost vs Kalshi?

Polymarket: 0% fees, only Polygon network costs (~$0.01/trade). Kalshi: up to 7% per trade plus spread. For high-frequency traders, Polymarket is dramatically cheaper.

What about Smarkets as an alternative?

Smarkets is a UK betting exchange with a lower default commission (2%) than Betfair. Liquidity on political markets is below Polymarket, comparable to Kalshi. Geo-blocked in many jurisdictions.

Which platform is accessible globally?

Polymarket is geo-blocked in the US/UK/EU. Kalshi is US-only. Betfair and Smarkets are UK-restricted. Robinhood Prediction Markets has a different geo footprint and routes to Polymarket's order book at 0% fees.

Are all these platforms regulated?

No. Kalshi is CFTC-regulated (US). Betfair and Smarkets are UK Gambling Commission licensed. Polymarket operates without explicit regulation — a different risk profile than a regulated sportsbook.