Highest temperature in Tokyo on July 30?

Platform comparison

Market context

Tokyo Haneda’s daily high for 30 July will be taken from Wunderground’s station history page, so the practical question is whether the airport site logs any late-afternoon spike before the settlement cut-off rather than whether central Tokyo feels hot in general. For a programme or bot, this is a simple data-scrape problem: poll the Haneda daily history endpoint, switch the units to °C, and map the reported maximum into the market’s temperature bands once the day is complete.

The 0% crowd price is anchored by history. Tokyo’s July highs at the official JMA station at 47662 typically sit in the low- to mid-30s °C, with the July record there at 39.5°C and several other top readings clustered around 37–39°C, while even Japan’s nationwide record has only recently reached 41.2°C elsewhere in the country.[6][7][9] That means a very high Haneda reading is not impossible in an extreme heatwave, but the base rate for Tokyo proper is materially below the most aggressive bins, which is why programmatic models would usually weight this as a tail-risk event unless the forecast ensemble is signalling exceptional heat.[6][7]

A trader should watch the Japan Meteorological Agency’s heat advisories, overnight temperatures, and whether inland western Japan heat shifts eastward into the Kantō plain, because Haneda’s airport setting can still register a late-day maximum if the urban heat island and weak winds coincide with strong insolation. The main dependency is the actual observed maximum before the market’s midday UTC cut-off, not the day’s headline national temperature, so automated workflows should re-check the source near the end of the local afternoon and avoid relying on news summaries that may report a record elsewhere in Japan rather than at Haneda itself.[5][9][12]

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

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.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.