Highest temperature in Tokyo on June 30?

Platform comparison

Market context

The real-world event hinges on the highest temperature recorded at Tokyo Haneda Airport on 30 June 2026, with the Japan Meteorological Agency forecasting cloudy skies and daytime highs in the mid-to-upper 20s Celsius. Current market data shows a 99% probability assigned to 27°C, while the crowd-implied probability for any outcome exceeding this range sits at 0%, reflecting a strong consensus that extreme heat is unlikely under the predicted conditions[1].

Historically, June in Tokyo has seen variable temperatures, with recent records showing a seven-day streak where central Tokyo failed to reach 25°C, contrasting sharply with Japan’s hottest June on record in 2025, when Nerima Ward hit 38.6°C[7][9]. This divergence frames the current 0% probability for higher ranges as a rational response to the immediate forecast of cloud cover and moderate highs, rather than a dismissal of Tokyo’s capacity for extreme heat.

Traders should monitor real-time updates from Wunderground and the Japan Meteorological Agency for shifts in cloud cover or sudden heat spikes, as these are the primary catalysts that could alter the settlement outcome[2]. Recent news highlights Japan’s experience of its warmest day on record, with Tamba city reaching 41.2°C, underscoring the need to watch for unexpected weather anomalies that could defy seasonal averages[8]. Programmatic approaches would involve querying Wunderground’s API for hourly data and setting conditional orders based on temperature thresholds exceeding 27°C.

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 Kalshi Fees, which mirrors the Polymarket order book directly.

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 Kalshi Fees. 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.

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.