Highest temperature in Tokyo on August 8?

Platform comparison

Market context

Tokyo’s highest temperature on 8 August is trading as a clear **underdog**, with the crowd pricing **0% YES** and consensus sitting around the low-to-mid 30s Celsius range rather than any extreme upside. Current forecasts are broadly in line: AccuWeather shows Tokyo near **92–94°F** for the day, timeanddate has a **94°F** high by early afternoon, and Yahoo Japan’s day forecast points to **35°C** for the city as a whole[2][7][9]. For this market, the relevant figure is the **Daily Observations** record at Tokyo Haneda Airport Station, not the summary high/low panel, so traders should be careful not to anchor to the easier-to-see headline number[8].

Historically, Tokyo in August tends to sit in a hot but fairly bounded regime, with typical daytime highs often in the low-to-mid 30s Celsius and sticky overnight conditions rather than sharp cool-downs[12][19]. That frames the favourite/underdog dynamic: the favourite outcome is a temperature range around the forecast peak, while the value angle for contrarians is that even a strong-looking heat forecast does not automatically translate into an upper-range print at the station if cloud cover, sea breeze, or timing keep the daily observation just below expectations[2][7][9]. With the market already at 0% YES, any edge is more likely to lie in whether the realised station maximum reaches the top of the forecast band than in a large consensus miss[1][3].

The main catalyst is the intraday evolution of heat and shower risk, because the listed forecasts show mostly sunny to partly cloudy conditions, with only a modest chance of thunderstorms later and little evidence of a rain-driven cap on daytime warming[2][3][6]. Traders should watch the midday-to-afternoon observations closely, since the peak is likely to be set before any late humidity or spot thunderstorm risk matters[2][3]. If the official Weather Underground daily observations update lag is the source of settlement, the practical dependency is on the station’s recorded maximum rather than broader city forecasts, which makes small local differences the key value spot[8].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Tokyo on August 8? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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

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.

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%.