Highest temperature in Tokyo on August 13?

Platform comparison

Market context

Tokyo's peak temperature on 13 August 2026 will be measured at Haneda Airport Station and recorded in Weather Underground's Daily Observations table—the granular, minute-by-minute dataset rather than the rounded summary figures. This distinction matters for resolution: the highest instantaneous reading during the calendar day, not an averaged or adjusted figure, determines the outcome. The settlement window closes at midday UTC, creating a practical constraint: traders must account for the fact that Tokyo's afternoon peak typically occurs between 14:00 and 16:00 local time, which falls after the resolution deadline.

August temperatures at Haneda have historically ranged between 28–35°C, with the station's all-time August high near 37°C. The 0% crowd probability suggests the market may be calibrated to a specific upper threshold that rarely materialises—likely 36°C or above. Comparable August days in 2023 and 2024 saw highs of 33–34°C; extreme heat events pushing toward 37°C occur roughly once per decade in Tokyo's records. A trader automating this market would need to cross-reference Haneda's historical variance against seasonal forecasts and flag any unusual atmospheric patterns (heat domes, pressure systems) that might shift the distribution.

Japan Meteorological Agency forecasts, published typically 10 days ahead, will be the primary leading indicator. Traders should monitor updates from mid-August onwards, particularly any alerts for exceptional heat. The Weather Underground API provides programmatic access to historical and real-time station data, enabling conditional orders triggered by specific forecast thresholds or live temperature readings as the settlement window approaches.

Methodology

We track Highest temperature in Tokyo on August 13? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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%.