Highest temperature in Tokyo on August 21?

Platform comparison

Market context

Tokyo's peak temperature on 21 August 2026 will be measured at Haneda Airport Station and recorded in Weather Underground's Daily Observations table, with the contract settling to whichever temperature band contains that figure. The market currently prices this event at 0% YES, meaning traders have assigned negligible probability to the specific outcome this contract represents—though the underlying event itself (a day in Tokyo with measurable heat) is meteorologically certain.

Historical August temperatures at Haneda show consistent patterns: the station recorded 35.1°C on 21 August 2023 and 34.4°C on the same date in 2022. The thirty-year August average high sits around 32–33°C, though extremes have reached 37–38°C during heat waves. The 0% pricing suggests either the contract's temperature band sits well outside typical ranges for that date, or traders view the resolution mechanism's reliance on Weather Underground's Daily Observations table as introducing sufficient friction to warrant extreme scepticism. Comparable Polymarket weather contracts on Polygon have shown that narrow temperature bands often trade at depressed prices simply because hitting a specific range requires precision rather than directional accuracy.

Traders monitoring this contract should track Japan Meteorological Agency forecasts released in early August 2026, which typically offer reliable ten-day outlooks. Pacific typhoon activity and upper-atmosphere pressure systems in late summer can shift Tokyo's temperatures by several degrees; the JMA's seasonal outlook and any tropical cyclone warnings will be critical signals. Settlement depends entirely on Wunderground's data capture at Haneda, making the exchange's operational status on 21 August a secondary but non-trivial dependency.

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to Polymarket Scam?, which mirrors the Polymarket order book directly.

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

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

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%.