Highest temperature in Tokyo on July 13?

Platform comparison

Market context

Tokyo faces its peak summer heat on 13 July 2026, with the market betting on the highest temperature recorded at Haneda Airport. Despite the current crowd-implied probability of 0% for a specific unlisted outcome, the broader prediction market on Polymarket strongly favours 31°C at 37%, followed by 30°C at 24%[2]. This divergence suggests the 0% line likely applies to an extreme outlier range, whereas the collective trader consensus aligns closely with Accuweather’s July 2026 forecast for Haneda, which projects daily highs between 25°C and 33°C (76°–91°F)[1].

Historical context reinforces the 30–32°C range as the statistical norm for mid-July in Tokyo, even as Japan recently shattered its all-time record with 41.2°C in Hyogo Prefecture last summer[7]. While the 2025 heatwave broke 17 records since 1898, Haneda Airport typically registers slightly lower peaks than inland cities due to coastal ventilation[10]. The market’s heavy weighting on 31°C reflects this regional moderation, contrasting with the 100% certainty traders assigned to a 29°C peak for the preceding day, 12 July[3].

Traders should monitor the Japan Meteorological Agency’s daily 5 AM UTC briefing for real-time heatwave advisories, which often trigger rapid odds shifts if temperatures breach 35°C[7]. Humidity levels exceeding 95% in mid-to-late July can amplify perceived heat, though the resolution source relies strictly on dry-bulb temperature from Wunderground[6]. Any sudden shift in the 31°C line will likely depend on overnight cloud cover forecasts, as clear skies typically drive Haneda’s maximums toward the upper forecast limit of 33°C[1].

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 Best Prediction Markets, 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 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.

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.