Highest temperature in Tokyo on August 8?

Platform comparison

Market context

Tokyo’s afternoon heat is trading at **0% YES** in this Polymarket contract, with conditional tokens on Polygon priced as though none of the listed temperature bands will land for the Haneda Airport station’s daily maximum. That makes the market look misaligned with the live weather picture: Polymarket’s own event page points to a Japan Meteorological Agency forecast of **34°C** for Tokyo on 8 August, while the market’s current leader is also **34°C at 100%**.[2] By design, resolution depends on the **Daily Observations** table at Weather Underground, not the headline day high/low summary, so traders need the recorded station maximum rather than the broader city forecast or summary display.[2]

For context, Tokyo in August usually sits in the low 30s Celsius, with long-run averages around **30–31°C** and frequent spikes above that during the peak of summer.[6][14][15] The market should therefore be read against a familiar seasonal baseline rather than as an outlier heat event. On comparable Polymarket weather contracts, the crowd has often converged tightly when the forecast is stable; one recent Tokyo temperature market resolved at **29°C**, showing how quickly the final print can matter more than the intraday perception of warmth.[18] Here, a 0% reading implies the current order book is either stale or waiting for a late repricing before the daily observation is fixed.

Traders should watch the **Weather Underground daily history feed for RJTT**, because the settlement clock runs until the first datapoint for the following date is published, after which revisions stop counting.[2] The key dependency is whether Haneda’s final observed high breaks into the next Celsius band before the station day rolls over in the source data. On-chain, that means the redeemable value of the winning conditional tokens is determined by a single published observation, not by broader Tokyo forecasts or the JMA city page, so any late update to the station record can move the contract sharply before expiry.[2]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to PolyGram, which mirrors the Polymarket order book directly.

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.

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%.