Highest temperature in Tokyo on July 31?

Platform comparison

Market context

Tokyo has already seen an intense late-July heat spell, with Japan setting fresh national temperature extremes this week and multiple inland locations above 40C. That matters because the probability for a Haneda reading above the market’s upper bands depends less on the headline national record and more on whether the coastal airport can briefly break out of the sea-breeze moderation that usually limits Tokyo’s peak heat. [9][15]

For Tokyo itself, late July highs are often in the low-to-mid 30s Celsius, but individual days can spike higher: recent July 31 examples in the city area include maxima around 33C to 36C, while Tokyo’s all-time official maximum at the central station level is 37C. Haneda has tended to run a little cooler than the inland urban core in recent JMA daily tables, including a 31.1C reading on 31 July 2025, which is a useful reminder that the airport site needs an exceptional set-up to get into the high 30s. [8][6][12]

The key traders’ watchlist is the day’s Tokyo temperature profile: early sunshine, afternoon boundary-layer heating, wind direction, and any shift that weakens the coastal breeze before the Wunderground daily high is finalised at midday UTC. The latest Japan-wide heat outbreak shows the atmosphere remains capable of extreme spikes, but Haneda’s location near Tokyo Bay makes sustained inland-style surges less common than at western or northern stations, so the market still prices the more typical airport-climate outcome even in a very hot national pattern. [9][14][5]

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?

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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.

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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.

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.