Highest temperature in Shanghai on July 31?

Platform comparison

Market context

Shanghai’s highest temperature on 31 July will be measured at Pudong International Airport, so the key question is whether the day’s peak lands in a hotter band than the current forecast suggests. The market’s 0% crowd-implied price sits against a forecast backdrop that is still very warm for late July: AccuWeather puts Shanghai’s daily highs around 91°F, while Weather.com shows a Pudong high near 95°F with showers and a meaningful chance of rain. [1][13]

Historically, late July is Shanghai’s hottest, muggiest period, with average highs around 33°C and some forecasts for 31 July clustering in the mid-30s Celsius. WeatherSpark notes 31 July is often among the clearer days of the month, which matters because cloud cover and showers can suppress the daytime maximum even when the air mass is hot. That means the market is really about the airport’s observed maximum, not the broader city forecast, and a single afternoon burst of heat can still settle the outcome into a higher Celsius band than traders expect. [1][12][16]

For platform comparison, Polymarket-style markets are typically quoted as implied probability, while Kalshi and Betfair/Smarkets-style books are easier to read in decimal-odds terms, so a 0% print may reflect sparse liquidity rather than a literal impossibility. The main catalysts are the final hourly forecast updates, any late-shifted rain or thunderstorm timing, and the actual Wunderground airport observation sequence through the settlement window. Fee treatment and access also differ: exchange-style venues generally add commission or fees on winnings and may require more extensive KYC, whereas prediction-market platforms often show the price more directly but can still be gated by jurisdiction. [9][13][17]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We read Highest temperature in Shanghai on July 31? 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.

Which platform has the deepest liquidity?

Polymarket — by a wide margin. Top markets reach $50-500M volume, Kalshi ~$200M cumulative, Betfair similar. Deeper liquidity means your trade moves the quote less.

Is Betfair a Polymarket alternative?

Only partially. Betfair Exchange is UK-focused with a sports-betting emphasis; they have politics markets but with thinner liquidity than Polymarket. Settlement in GBP/EUR, 2-5% commission on winnings.

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.

Which platform supports Klarna/SOFORT?

Directly: none. Polymarket accepts only USDC on Polygon. Robinhood Prediction Markets offers a fiat on-ramp via Klarna or SOFORT (DE/AT/CH) and converts internally to USDC for the Polymarket order book. T+1 processing.