Highest temperature in Tokyo on July 4?

Platform comparison

Market context

The underlying event is the peak daily temperature recorded at Tokyo Haneda Airport on 4 July 2026, a date historically prone to extreme summer heat in the Kanto region. With the crowd-implied probability for the "YES" outcome sitting at 0%, the market currently treats any temperature above a specific threshold as virtually impossible, reflecting a consensus that the day will remain cool or that the threshold is set impossibly high. This stark pricing ignores Japan’s recent trajectory of record-breaking July heat, where the nationwide average hit 2.89°C above normal for the third consecutive year, suggesting the underdog (the hot outcome) holds significant value against the favourite (the cool outcome)[3].

Historical precedents frame this 0% pricing as a contrarian trap rather than a rational assessment. In 2024, Japan sweltered through its hottest July in recorded history, with temperatures exceeding 40°C in seven locations and reaching 41.0°C in Sano, while Tamba city recently recorded a scorching 41.2°C[6][7]. Even a recent prediction for Tokyo on 2 July 2026 settled at 24°C, indicating that mid-July heat is already active, yet the market for the 4th dismisses higher extremes entirely[1]. Traders should watch for immediate meteorological updates from the Japan Meteorological Agency and local humidity forecasts, as the NCEI Past Weather Tool confirms that Haneda’s microclimate can spike rapidly under high-pressure systems[2][4]. The value lies in betting against the 0% consensus, given the documented trend of escalating summer temperatures across the nation.

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 Who Will Win, which mirrors the Polymarket order book directly.

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 Who Will Win. 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.