Highest temperature in Tokyo on August 18?

Platform comparison

Market context

Tokyo's maximum temperature on 18 August 2026 will be measured at Haneda Airport Station and recorded in Weather Underground's Daily Observations table. The settlement window closes at midday UTC on that date, meaning final readings must be captured before the afternoon peak temperatures typically occur in Tokyo's summer climate. Current crowd pricing reflects 0% implied probability, suggesting traders have assigned negligible likelihood to certain temperature thresholds within this market's range structure.

August represents Tokyo's warmest month, with historical daily highs averaging 32–33°C and regularly exceeding 35°C during heat waves. The 2023 summer saw multiple days above 37°C in the capital, whilst the 2010 heat wave produced readings near 40°C. These precedents establish that extreme heat outcomes carry material probability during mid-August, yet the current market pricing suggests either consensus around a narrow temperature band or substantial disagreement about which specific range will resolve. Cross-platform comparison data remains sparse given the market's specificity and forward-looking nature.

The Japan Meteorological Agency issues seasonal forecasts and weekly outlooks that traders should monitor through July and early August 2026. Pacific high-pressure systems and potential typhoon activity represent primary catalysts affecting temperature outcomes during this period. Discrepancies between Weather Underground's Daily Observations table and its Day High & Low summary section have historically occurred, making source verification critical; traders should familiarise themselves with Haneda's specific recording methodology before settlement approaches.

Methodology

We track Highest temperature in Tokyo on August 18? 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.

FAQ

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 PolyGram. 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.

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.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like PolyGram trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.