Highest temperature in Tokyo on August 20?

Platform comparison

Market context

Tokyo's weather on 20 August 2026 will depend heavily on the strength and positioning of the Pacific high-pressure system during late summer, when the city typically experiences its most intense heat. The 0% crowd probability suggests traders are either uncertain about the resolution mechanics or treating this as a placeholder market ahead of the settlement window. August temperatures at Haneda Airport Station routinely exceed 30°C, with historical records showing peaks between 35–37°C during typical summer conditions.

Tokyo's August climate sits within a well-documented pattern: the city has recorded temperatures above 35°C on 20 August in multiple years, most recently in 2023 when the daily high reached 35.5°C. The distinction between Weather Underground's Daily Observations table and the Day High & Low summary matters operationally, as the former captures sub-hourly readings and may register slightly different peaks depending on measurement timing. Comparable late-August dates show consistent clustering in the 32–36°C range at Haneda, providing a baseline for evaluating which temperature bracket becomes most probable as August 2026 approaches.

Traders should monitor Japan Meteorological Agency forecasts released in early August, which will clarify whether a typical Pacific high or an anomalous weather pattern dominates the period. El Niño or La Niña conditions, if present, could shift seasonal expectations. The settlement window closes at midday UTC on 20 August, giving traders a narrow window to adjust positions once actual morning temperatures become visible. Haneda's consistent measurement standards make this resolution straightforward once the date arrives, though current probability placement suggests the market may be awaiting clearer seasonal forecasting data.

Methodology

This page reviews Highest temperature in Tokyo on August 20? 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 Prediction Today, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

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

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.

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%.