Highest temperature in Tokyo on August 18?

Platform comparison

Market context

The market is pricing the peak temperature at Tokyo Haneda Airport on 18 August 2026 at 0% probability across all ranges, suggesting either extreme confidence in a specific outcome or insufficient liquidity to establish meaningful odds. August in Tokyo typically sees daily highs between 32–35°C, with occasional peaks above 36°C during heat waves. The settlement mechanism relies on Weather Underground's Daily Observations table rather than summary figures, which can differ materially depending on measurement timing and station calibration.

Historical August data from Haneda shows considerable year-to-year variation. In 2023, the 18th recorded 33.8°C; in 2022, it reached 35.4°C. The broader pattern suggests temperatures in the 33–36°C band are most common, though outlier years have produced readings above 37°C when Pacific high-pressure systems dominate. The current 0% pricing likely reflects either a crowd consensus around a single narrow range or thin order books rather than genuine certainty about the outcome.

Traders should monitor Japan Meteorological Agency forecasts issued in early August, which typically provide reliable 10-day outlooks. El Niño or La Niña conditions heading into summer 2026 will influence whether the Pacific anticyclone strengthens, potentially driving temperatures toward the upper end of the historical distribution. Urban heat island effects around the airport have intensified over the past decade, making comparisons to pre-2015 data less reliable. The resolution source specification—prioritising Daily Observations over summary highs—creates a technical edge for traders familiar with Wunderground's data architecture and potential discrepancies between reporting methods.

Methodology

This page reviews Highest temperature in Tokyo on August 18? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Who Will Win 2026, which mirrors the Polymarket order book at 0% fees.

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.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Who Will Win 2026 trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

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.