Highest temperature in Tokyo on July 28?

Platform comparison

Market context

Tokyo's maximum temperature on 28 July 2026 will be measured at Haneda Airport Station and resolved against historical weather data from Wunderground. The settlement window closes at midday UTC, meaning traders must account for the full calendar day in Tokyo (UTC+9) before the market locks. This timing creates a practical constraint: the highest temperature typically occurs in mid-afternoon local time, so resolution data will be available only after the market has already closed to new positions.

July temperatures at Haneda have historically ranged between 28°C and 37°C during the peak summer season, with the 30-year average high around 31–32°C. The 0% crowd probability suggests either extreme confidence in a specific temperature band or insufficient liquidity across all outcome ranges. Comparable July days in recent years—2023 saw 34.8°C, 2022 reached 33.1°C—provide calibration points, though individual daily variation remains substantial. A trader automating position entry would need to weight seasonal normals against any anomalous weather patterns developing in late July 2026.

The Japan Meteorological Agency publishes extended forecasts roughly two weeks in advance, with meaningful updates arriving five to seven days before the settlement date. Traders monitoring programmatically should track any heat wave advisories or unusual atmospheric pressure systems affecting the Kanto region. Wunderground's historical data feed updates daily, allowing conditional order systems to verify resolution criteria automatically once the market closes, though manual confirmation against the source URL remains prudent given the specificity of the Haneda station measurement requirement.

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

Resolution & payout

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

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 Polymarket Review UK. 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.