Highest temperature in Guangzhou on July 21?

Platform comparison

Market context

On 21 July 2026, the highest temperature recorded at Guangzhou Baiyun International Airport will determine the settlement outcome. Guangzhou sits in southern China's subtropical zone, where July represents the peak of the summer monsoon season. Historical July highs at this station typically range between 32–35°C, though extreme heat events occasionally push readings above 37°C. The 0% crowd probability suggests traders are either awaiting outcome brackets to be published or treating this as a placeholder market pending full specification.

Guangzhou's July temperatures correlate strongly with the East Asian summer monsoon intensity and occasional tropical cyclone activity in the South China Sea. The China Meteorological Administration issues seasonal forecasts in June that often signal whether the coming month will trend hotter or cooler than the 30-year normal. Traders monitoring this market should track any official heat warnings issued by Guangzhou authorities in early July, as these typically precede sustained high-temperature periods. Recent years have seen occasional July peaks exceed 36°C during particularly strong anticyclonic systems.

Platform divergence on this market reflects broader structural differences: Polymarket uses decimal odds and settles via Chainlink oracles, requiring traders to verify Wunderground's historical data feed independently; Kalshi and Betfair both offer fractional odds but differ on KYC requirements and regional access, with Kalshi's US-focused regulatory framework potentially limiting non-US participation. Smarkets' commission structure (5% on winnings) contrasts with Polymarket's fee model, affecting expected value calculations across identical temperature brackets. Settlement timing at 12:00 UTC on 21 July creates a hard deadline for all platforms, though data latency between Wunderground and oracle confirmation may vary by hours.

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 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.

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.