Highest temperature in Tokyo on July 31?

Platform comparison

Market context

Tokyo’s daytime heat on 31 July will decide this contract, with settlement tied to the highest temperature recorded at Haneda Airport Station during the day, not the citywide forecast headline. The market is already priced at **0% YES** despite public forecast services pointing to a hot end-July pattern: AccuWeather shows Tokyo highs around **84°F** for 31 July, while WeatherSpark says July 31 is typically one of Tokyo’s clearest days and sits near the upper end of the month’s average highs.[1][18]

That gap is best read against July climatology, which usually places Tokyo’s high temperatures in the low-to-mid 30s Celsius by month-end, with late-July being among the warmest and sunniest periods of the year.[18][19] The comparison set matters because the market is narrowly defined by a single station reading and the day’s maximum, so a small shift in cloud cover, sea breeze, or thunderstorm timing can change the outcome more than broad regional forecasts suggest. FNN’s latest JMA-based outlook for Tokyo calls for a **36°C** high, which is materially above the low implied probability and suggests the contract is trading well below the consensus weather view.[5]

For catalysts, traders should watch the official Japanese forecast updates and any afternoon convective development, because Tokyo’s realised maximum often comes before showers or cloud build-out arrive.[5][18] Hourly services are already flagging a rapid climb through the morning into the mid-30s Celsius by early afternoon, with thunderstorms mentioned in some outlooks, which can cap further heating if they arrive early enough.[3][9] There is no obvious sportsbook analogue for a weather high-temperature contract, so the useful comparison is between the prediction market’s near-zero pricing and the broader forecast stack, which is currently much higher.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Tokyo on July 31? 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.

FAQ

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

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.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Best Prediction Markets trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.