Highest temperature in Tokyo on August 12?

Platform comparison

Market context

Tokyo's weather on 12 August 2026 will depend heavily on the timing and intensity of the East Asian summer monsoon system active during that period. August typically sees peak heat in Tokyo, with daily highs averaging 32–34°C, though the specific daily maximum can vary considerably depending on cloud cover, wind patterns, and whether tropical systems influence the region. The 0% crowd probability suggests traders are either uncertain about the exact temperature threshold being tested or expect conditions to fall outside the specified range.

Historical August temperatures at Tokyo Haneda provide the essential baseline for calibration. Over the past two decades, daily highs in mid-August have ranged from approximately 28°C during cooler, wetter years to 37°C during heat-dome events. The Japan Meteorological Agency's seasonal outlooks, typically released in late July, will offer the most concrete guidance on whether August 2026 tracks toward above-normal or near-normal heat. Comparable years—such as August 2023, which saw sustained temperatures above 35°C—illustrate how monsoon positioning and high-pressure systems can push daily maxima well into the upper range.

Traders should monitor the JMA's monthly forecast release in late July 2025 and track any tropical cyclone activity in early August that might alter wind patterns or cloud coverage. Real-time weather models from mid-August onwards will narrow uncertainty significantly, though the resolution source's reliance on Weather Underground's Daily Observations table—rather than summary figures—means the precise station reading at Haneda will be decisive. Any discrepancy between preliminary reports and the final Daily Observations entry could affect settlement.

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

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

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.

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%.