Highest temperature in Tokyo on August 7?

Platform comparison

Market context

Tokyo’s heat has already been leaning hot in the first week of August, with the Japan Meteorological Agency showing a 35.6°C high at Haneda on 1 August and 33.0°C on 2 August in its Tokyo-area daily records, while broader August norms for Tokyo sit around 31°C and often push above 30°C in peak summer.[1][2] Against that backdrop, the market’s 0% yes price is best read as a sceptical starting point rather than a forecast of a cool day: a sub-30°C outcome would be well below what is typical for the season, but the settlement is tied to the *highest* reading in the Daily Observations table, not the headline day-high box.[1][3]

For comparable cases, Tokyo’s August climate usually leaves plenty of room for an upper-30s spike when clear skies and weak wind line up, and weather services continue to describe August as the city’s hottest month with persistent humidity and daytime highs often in the low 30s.[2][11][12] That matters because the market resolves on a single station reading at Haneda, so small shifts in cloud cover, sea breeze, or convective showers can move the final band materially even if the broader city feels similar.[1][3]

The main catalysts to watch are the morning-to-midday evolution in Tokyo observations, any Bureau of Meteorology-style advisories from Japanese forecasters, and whether marine-influenced cooling reaches Haneda before the day’s maximum is logged.[1][14] Since the window closes at 12:00 UTC, the crucial trader question is whether the peak is set before then; a late local-afternoon spike would be irrelevant here if it falls after settlement.

Sources: 1 · 2 · 3 · 4 · 5

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

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.

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.

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%.