Highest temperature in Tokyo on August 19?

Platform comparison

Market context

On 19 August 2026, Tokyo Haneda Airport Station will record its highest temperature for that date. The market currently prices this contract at 0% YES across all temperature bands, reflecting the settlement window's two-year horizon and the inherent difficulty in forecasting specific weather outcomes at such distance. Polymarket's conditional token structure on Polygon means traders are effectively pricing the probability that the Daily Observations table at Weather Underground will capture a reading within their chosen range—a distinction that matters, since the market explicitly prioritises this granular dataset over the Day High & Low summary section.

Tokyo's August climate presents a relatively stable meteorological baseline. Historical data from Haneda shows mid-August highs typically cluster between 32–35°C, with extreme readings above 37°C occurring in roughly one year per decade during particularly intense heat waves. The 2010 heat wave pushed temperatures to 39.9°C in central Tokyo, though Haneda's coastal location moderates such extremes. Current pricing at 0% suggests the market has not yet calibrated to seasonal norms or assigned meaningful probability mass to any specific temperature band, which is unsurprising given the contract's distant settlement date and the absence of near-term meteorological forecasts.

Traders should monitor Japan Meteorological Agency announcements in summer 2026, particularly any El Niño or La Niña advisories that could shift regional temperature patterns. Seasonal forecasts issued in June and July 2026 will provide the first concrete signals about whether August conditions favour above-normal or below-normal temperatures. The specificity of the Weather Underground Daily Observations requirement means traders must also verify Haneda's sensor calibration and data reporting practices closer to the settlement window.

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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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 Scam?. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

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%.