Highest temperature in Tokyo on August 5?

Platform comparison

Market context

Polymarket prices this Tokyo heat contract at **0% YES**, so the market is currently treating a qualifying high at Haneda as effectively absent even though the live weather picture still points to a hot August day in the capital. Tokyo’s early-August forecast sits around the high-20s to low-30s Celsius, with AccuWeather showing highs of roughly 29–31°C for 5 August and a month profile that still runs into the mid-30s Fahrenheit-equivalent range on hotter days[1][4][8].

For context, this is a threshold market on the *daily maximum* at Tokyo Haneda Airport Station, settled in **USDC** on **Polygon** through **conditional tokens**, so only the exact Wunderground reading matters at the cut-off, not broader city-wide weather or what happens later in the day. Historical and forecast data suggest Tokyo in August often peaks near 30–35°C, and JMA daily records for Tokyo have already shown maxima above 35°C earlier in the month, which is the sort of comparison traders use to judge whether the market’s zero bid is simply conservative or genuinely anchored to the source measure[7][10][14][17].

The main catalyst is the intraday temperature path before the settlement window closes at **12:00 UTC**, because the contract resolves off the highest temperature recorded on 5 August at the specified station, not a noon snapshot. Traders should watch the official Wunderground history page for the Haneda station, along with any sharp deviations from the forecast caused by sun breaks, humidity, or passing showers; current hourly models show temperatures rising into the high 20s Celsius by late morning, with low precipitation odds in some forecasts but scattered-cloud conditions that could still affect the peak reading[2][3][6].

Sources: 1 · 2 · 3 · 4 · 5

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 PolyGram. 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.

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.