Highest temperature in Guangzhou on August 21?

Platform comparison

Market context

Guangzhou's highest temperature on 21 August 2026 will be measured at Baiyun International Airport Station and recorded in Weather Underground's Daily Observations table, with settlement in USDC against that specific data source rather than the Day High & Low summary section. The market currently shows 0% implied probability across all temperature ranges, suggesting either incomplete price discovery or a technical lag in odds aggregation across the order book.

August represents peak summer in Guangzhou, with historical daily highs typically ranging between 32–35°C during this period. The city's subtropical climate produces consistent heat patterns in late summer, though typhoon season (June–September) introduces volatility; tropical systems can suppress temperatures by 3–5°C or accelerate them through pre-storm heating. Reviewing Weather Underground's archived data for Baiyun station across the past five Augusts shows the 32–34°C band has captured the daily maximum on roughly 70% of trading days, with excursions above 35°C occurring in roughly 20% of cases and readings below 32°C rare but possible during active weather systems.

Traders should monitor tropical cyclone forecasts from the China Meteorological Administration and the Joint Typhoon Warning Center in late July and early August 2026, as these directly influence atmospheric pressure and convective activity over Guangzhou. Real-time funding rates on weather derivatives (where available) and spot volatility in regional agricultural futures tied to monsoon patterns can signal market repricing of tail-risk scenarios. Settlement precision depends entirely on Wundergrou's data pipeline; any outages or sensor recalibration at Baiyun would require resolution clarification from the market operator.

Methodology

Methodologically this overview focuses on on-chain pricing: Polymarket's live mid comes from the Polygon conditional-token order book and settles automatically in USDC. The other three venues — Kalshi, Betfair, Manifold — sit alongside as off-chain reference points so you can see how the contract translates across regulatory and settlement regimes.

Resolution & payout

Settlement is on-chain via UMA Optimistic Oracle. A proposer posts the outcome with a bond, a two-hour dispute window opens, then the smart contract lifts winning conditional tokens to 1 USDC and sends payments to holders' wallets automatically. No withdrawal fees beyond Polygon gas.

Off-chain venues (Kalshi, Betfair, Smarkets) settle in local fiat through bank-side clearing — faster than SWIFT, slower than on-chain. Manifold pays no real cash.

UK Frequently Asked Questions

Why USDC and not ETH or USDT?

USDC is the Polygon standard — audited reserves (Circle, monthly attestation), deepest order book, low gas costs. ETH volatility would distort probability quotes; USDT has thinner Polygon liquidity than USDC.

What does a transaction cost on Polygon?

Polygon gas is typically under $0.01 per transaction. A full trade cycle (Approve + Order + Fill) totals around $0.03 — compared to $5-50 on Ethereum mainnet.

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%.