Highest temperature in Tokyo on August 17?

Platform comparison

Market context

On 17 August 2026, the highest temperature recorded at Tokyo Haneda Airport will fall into one of several defined ranges. Prediction markets let traders buy YES or NO shares on specific outcomes: a YES share pays out if the event occurs, a NO share if it doesn't. Here, traders are essentially wagering on which temperature bracket will contain that day's peak reading, measured in degrees Celsius and sourced from Weather Underground's Daily Observations table at Haneda station.

Tokyo's August temperatures are remarkably consistent. Historical data shows daily highs in mid-August typically cluster between 32–35°C, with extremes rare. The 0% crowd probability suggests traders are pricing in either a very narrow or very high temperature range for this particular market option. August is Tokyo's hottest month, but the city's maritime location and urban heat island effects create predictable patterns; records from the past decade show few surprises in the 17–18 August window specifically.

The Japan Meteorological Agency publishes seasonal forecasts and updates its medium-range outlook regularly, which often influences market sentiment around specific dates. Traders should monitor late July and early August forecasts for any signals of unusual heat waves or cooler systems approaching the Kanto region. El Niño or La Niña conditions, tracked by NOAA and reported widely, can shift summer temperatures across East Asia. Settlement occurs at 12:00 UTC on 17 August 2026, so the market closes before Haneda's final daily observation is typically recorded, making real-time weather data crucial to final positioning.

Methodology

We track Highest temperature in Tokyo on August 17? 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

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 Prediction Market UK. 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%.