Highest temperature in Shenzhen on July 21?

Platform comparison

Market context

Shenzhen faces its peak summer heat on 21 July 2026, with the Shenzhen Bao'an International Airport Station expected to record a daily maximum near the city’s typical July high. Historical data shows July is Shenzhen’s hottest month, averaging a daytime high of 32°C (90°F) alongside 17 rainy days and heavy subtropical precipitation driven by the regional high and potential typhoon activity[2].

The current market assigns a 98% probability to 31°C as the outcome, with 32°C holding just 2%, suggesting traders expect cloud cover or rain to suppress temperatures slightly below the monthly average[1]. This divergence from the 32°C historical mean contrasts with platforms like Kalshi or Betfair, which often price weather events using decimal odds rather than implied probability, while Polymarket’s non-KYC access and lower fee structure attract retail flow that can skew probabilities away from climatological baselines compared to regulated books.

Traders should monitor the National Meteorological Centre of China’s daily typhoon and rainfall bulletins, as a passing system could drop temperatures below 30°C, invalidating the 31°C frontrunner. Wunderground’s hourly records for ZGSZ will determine settlement, and any sudden shift in the subtropical high’s position could alter the day’s peak temperature within hours of the 12:00 UTC settlement window[2].

Sources: 1 · 2

Methodology

This page compares Highest temperature in Shenzhen 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

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

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.

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.

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.