Highest temperature in Shenzhen on August 7?

Platform comparison

Market context

Shenzhen’s airport temperature on 7 August will be set by the highest reading in Weather Underground’s Daily Observations table, not the day-summary headline, so programmatic monitoring should pull the station feed directly and ignore any cached “high” figure that may differ. The current crowd price of 0% implies the market is treating every listed Celsius band as effectively unresolved rather than assigning meaningful odds to a specific peak.

For context, Shenzhen is a hot, humid August city, with typical highs around 32°C and forecast-style products often showing 35°C or 36°C as plausible on the warmest days[1][5][10][15]. That matters because this market resolves to a discrete temperature band, so a trader building tooling would normally model the airport station’s intraday extrema, then map the observed maximum into the platform’s outcome buckets rather than using citywide averages[11]. In other words, the useful variable is not “what did Shenzhen feel like?”, but “what exact Celsius value did the station log before the settlement cutoff?”

The key catalysts are the hourly observation updates, any late-afternoon spike, and weather-system changes that can push the daily maximum higher or cap it below the hotter forecast bands. August is also part of Shenzhen’s wet season, and external forecasters note a persistent risk of heavy rain and typhoon influence in this period, which can suppress daytime highs or create sharp pre-rain warmth[10][19]. For a bot or conditional-order workflow, the practical check is a scheduled scrape of the Daily Observations table up to 12:00 UTC, with alerting on the highest timestamped temperature rather than the final summary field.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

UK Frequently Asked Questions

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Polymarket Review UK. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

Is Polymarket legal in the UK?

Polymarket is accessible to UK traders but is not UKGC-licensed. It operates under US CFTC jurisdiction. UK residents face no domestic legal prohibition on using it, but UKGC consumer protections do not apply. For UKGC-regulated alternatives, Betfair Exchange and Smarkets offer similar prediction-style markets.

Do I pay tax on prediction market profits in the UK?

UKGC-licensed platform profits (Betfair, Smarkets) are typically tax-free gambling winnings for UK individuals. Polymarket profits involve USDC crypto transactions, which HMRC treats as Capital Gains Tax events. Keep full transaction records and report via Self Assessment if gains exceed £3,000 per tax year.

How do I deposit on Polymarket from the UK?

UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.