Highest temperature in Shenzhen on August 21?

Platform comparison

Market context

The market resolves on the highest temperature recorded at Shenzhen Bao'an International Airport on 21 August 2026, measured in degrees Celsius via Weather Underground's Daily Observations table. The 0% crowd probability reflects either extreme confidence in a specific temperature range or sparse trading activity on this niche weather contract. Settlement occurs in USDC at 12:00 UTC on the resolution date, with the precise measurement sourced from the airport's official meteorological station rather than summary forecasts.

Shenzhen's August climate presents a narrow historical band for prediction. The city experiences peak summer heat in mid-August, with daily highs typically ranging between 32–35°C. Over the past decade, extreme readings above 36°C have occurred roughly once per August season, whilst temperatures below 31°C are exceptionally rare during this period. The 0% probability suggests traders have already committed to a specific temperature bracket, or the market lacks sufficient liquidity to establish a consensus baseline. Comparable weather markets on prediction platforms show that tropical coastal cities with stable seasonal patterns often exhibit concentrated probability distributions once trading begins.

Traders should monitor tropical cyclone activity across the western Pacific and any anomalous heat systems developing in early August 2026. China's meteorological forecasts, typically released 10–14 days ahead, will provide directional signals. Funding rates on perpetual weather derivatives and on-chain activity around settlement dates on other climate-linked contracts may indicate broader macro positioning. The resolution window's timing at midday UTC aligns with Shenzhen's afternoon peak, when maximum temperatures are typically recorded.

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%.