Highest temperature in Guangzhou on July 21?

Platform comparison

Market context

Guangzhou will experience peak summer heat on 21 July 2026, with the settlement hinging on the single highest temperature reading at Baiyun International Airport Station that day. The market resolves using Wunderground's historical weather data, which records hourly observations and derives the daily maximum. This specificity matters: airport stations typically sit in open terrain with minimal shade, often recording 2–3°C higher peaks than urban centres. Guangzhou's July climate is dominated by the East Asian summer monsoon, producing sustained heat and humidity; daily maxima routinely exceed 33°C during this period, with occasional readings above 36°C during heat waves.

Historical July records for Guangzhou show considerable year-to-year variance. The city's average July high sits near 33°C, but extremes range from 31°C in cooler years to 38°C during intense heat episodes. The 0% crowd probability currently assigned suggests either sparse liquidity or a market-wide view that the specific temperature threshold being priced is implausibly high. Across platforms—Polymarket, Kalshi, Betfair, and Smarkets—weather markets often show thin order books for precise temperature bands, particularly those representing tail outcomes. Kalshi's US-focused regulatory framework and Polymarket's broader international coverage create different liquidity profiles; Betfair and Smarkets typically offer decimal odds formats that can obscure implied probabilities for casual traders unfamiliar with conversion.

Watch for seasonal forecasts from the China Meteorological Administration, typically issued monthly, which flag heat wave risks. El Niño or La Niña conditions influence East Asian monsoon strength and should be monitored through June 2026. No scheduled events directly alter Guangzhou's weather, but tropical cyclone activity in the South China Sea occasionally modulates temperature patterns in late July.

Methodology

This page compares Highest temperature in Guangzhou on July 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 Kalshi Alternative UK, 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

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.

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.

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. Kalshi Alternative UK 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.