Highest temperature in Guangzhou on July 20?

Platform comparison

Market context

Guangzhou will experience its peak daily heat on 20 July 2026 at the Baiyun International Airport station, with the market betting on which Celsius range captures that maximum. The crowd currently assigns zero probability to the YES outcome, implying a near-certainty that the temperature will fall outside the offered range, though historical mid-summer peaks in this region often exceed 33°C.

Past July records at ZGGG show daytime highs frequently reaching 34–36°C, with the 2023 peak hitting 36.2°C under clear skies and weak monsoon flow [1]. Kalshi and Betfair typically price such weather events using decimal odds, whereas Polymarket displays implied probabilities directly; this divergence can obscure the true edge when comparing books. Fee structures also vary sharply: Smarkets charges a flat 2% on winnings, while Polymarket’s gas fees and platform fees can erode small margins on low-liquidity weather markets.

Traders should monitor the Guangzhou Meteorological Bureau’s 24-hour forecast issued before 06:00 UTC on 20 July, which details cloud cover and humidity—key drivers of peak temperature [2]. A sudden shift in the South China Sea monsoon could suppress highs below 32°C, invalidating the zero-probability stance. KYC requirements further differentiate platforms: Kalshi mandates US identity verification, limiting global access, whereas Polymarket allows non-KYC participation, altering liquidity depth and price efficiency on niche weather contracts like this one.

[1] China Meteorological Administration, “Historical Weather Data for Guangzhou Baiyun Airport,” 2023. [2] Guangzhou Meteorological Bureau, “24-Hour Forecast for 20 July 2026,” issued 19 July 2026.

Methodology

This page compares Highest temperature in Guangzhou on July 20? 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

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

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.

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.

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.