Highest temperature in Tokyo on August 19?

Platform comparison

Market context

The market is pricing the peak temperature at Tokyo Haneda Airport on 19 August 2026 at 0% probability across all temperature bands, suggesting either extreme confidence in a specific narrow range or minimal trading activity. August in Tokyo typically sees daily highs between 32–35°C, with occasional peaks above 36°C during heat waves. The settlement hinges on Weather Underground's Daily Observations table rather than the summary high-low figures, a distinction that matters when automated stations record micro-fluctuations or when multiple readings occur across a single day.

Historical August temperatures at Haneda show considerable year-to-year variation. The 30-year average high sits around 32.5°C, but the station has recorded 38°C+ on multiple occasions, most recently during the 2019 and 2023 heat waves. The 0% crowd probability likely reflects either a data lag in market initialisation or traders awaiting clearer seasonal forecasts before committing capital. Given that August 2026 forecasting remains speculative at this distance, the current odds present potential value for those confident in either typical summer conditions or an above-average heat event.

Traders should monitor Japan Meteorological Agency seasonal outlooks released in July 2026, which typically indicate whether Pacific high-pressure systems will dominate or whether cooler patterns might prevail. El Niño or La Niña conditions in the preceding months could shift expectations materially. The specific resolution source—Haneda's automated observations rather than manual readings—means that any station maintenance or sensor recalibration scheduled for mid-August could theoretically affect recorded values, though such disruptions are rare and usually flagged in advance.

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

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.

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 Who Will Win 2026. 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.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.