Highest temperature in Tokyo on August 4?

Platform comparison

Market context

Tokyo has started the day with a warm pre-dawn baseline rather than a cool morning reset, and that matters because the market settles on the *highest* reading at Haneda rather than the average. Current hourly guidance for Tokyo shows temperatures already in the mid-20s °C before sunrise, while the broader August outlook keeps daytime highs centred in the low 30s °C, so the day still has room for a meaningful lift if sunshine breaks through.[2][1]

The crowd is effectively pricing a very low-end outcome at 0% YES, but Tokyo’s August climate gives the opposite frame: typical monthly highs are around 31–35°C, with humidity and intermittent rainfall making heat spikes common rather than exceptional.[10][14][16] Recent Tokyo data from the Japan Meteorological Agency also shows Haneda reaching 35.6°C on 1 August and 35.3°C on 2 August, which is consistent with the airport being able to post a high in the mid-30s on a hot summer day.[8][10]

For traders, the main catalysts are the daytime heating profile, cloud cover, and any rain bands moving through the capital, with the highest temperature usually set in the early to mid-afternoon if skies clear.[3][7] The practical dependency is whether showers or thicker cloud suppress insolation enough to cap the day below the recent early-August levels; if not, Haneda can still print a high well above the current implied bar.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Highest temperature in Tokyo on August 4? 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

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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

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.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.