Highest temperature in Shanghai on August 21?

Platform comparison

Market context

Shanghai's highest temperature on 21 August 2026 will be measured at Pudong International Airport Station and recorded in Weather Underground's Daily Observations table, with settlement based on which temperature band the peak reading falls into. The current 0% implied probability suggests traders are either awaiting clearer seasonal forecasts or treating this as a placeholder market pending resolution criteria clarification.

August in Shanghai typically peaks between 32–35°C, though extreme heat events pushing toward 37–39°C occur roughly once per decade during particularly intense summer patterns. The 2013 heatwave saw Shanghai record 38.3°C in mid-August, whilst more recent years (2022–2024) have shown peaks in the 33–35°C range. Historical volatility across the decade means the current zero probability may reflect uncertainty about which temperature band the market is actually pricing, rather than dismissal of heat occurring. Traders comparing this across platforms—Polymarket's decimal odds format versus Kalshi's binary structure—will find the resolution source specification (Daily Observations rather than Day High & Low summaries) critical for avoiding settlement disputes common on weather markets.

Monitoring begins with China Meteorological Administration forecasts released in early August 2026, typically 10–14 days ahead of the target date. Tropical cyclone activity in the Western Pacific during late summer can suppress Shanghai temperatures by 2–4°C, whilst high-pressure systems stalled over eastern China drive sustained heat. The specific settlement window closing at 12:00 UTC on 21 August means traders must account for the time-zone offset; Shanghai operates UTC+8, so the window closes at 20:00 local time, potentially excluding late-afternoon temperature spikes.

Methodology

This page compares Highest temperature in Shanghai on August 21? specifically across Polymarket, Kalshi, Betfair Exchange and Smarkets. The live probability is the Polymarket mid; the comparison columns summarise each venue's fee structure, KYC, settlement currency and payment rails. Every CTA routes to Robinhood Prediction Markets, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Settlement is the biggest difference between the four platforms: Polymarket on-chain in USDC (instant), Kalshi USD via CFTC (T+1), Betfair and Smarkets in local currency via bank withdrawal (T+1 to T+3). On-chain settlement clears in minutes — the fastest payout path of the four.

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.

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.

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.

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.