Highest temperature in Tokyo on July 31?

Platform comparison

Market context

Tokyo’s highest temperature on 31 July is a *weather* settlement, and the market is currently priced at **0% YES**, which leaves the favourite firmly on the *no-hit* side unless an exceptional afternoon spike develops. The consensus view is that Haneda usually tracks Tokyo’s summer heat rather than the more extreme inland hotspots, so the value case for **YES** sits with traders expecting a broad Tokyo-wide heat surge to reach the airport station as well. Recent Japanese extremes show the ceiling can jump quickly: national records were reset at 41.2°C in Tamba on 30 July 2025 and then 41.8°C in Isesaki later that month, while Tokyo itself has historically sat well below those inland peaks.[9][14]

For handicapper’s framing, the market looks like a classic *low-probability favourite* trade: **NO** is the market’s consensus, while **YES** is the contrarian angle only if the heat dome strengthens over eastern Honshū. July climatology for Tokyo is hot but not usually record-breaking, with average July highs around 30°C and recent end-of-month readings in the low-to-mid 30s rather than the extreme 40s seen elsewhere in Japan.[11][12] That historical spread matters because Haneda’s airport location near the bay can moderate peaks versus inland wards, making the upper tail narrower than headline national records suggest.[8][10]

Traders should watch the midday-to-afternoon forecast trend, not just the morning setup, because the settlement source is the *day’s highest* reading at Tokyo Haneda Airport Station and late heat maximisation can change the range outcome. Key catalysts are any upgraded JMA heat advisories, the persistence of clear skies and weak wind, and whether the current regional heat wave extends eastwards across the Tokyo plain; recent reporting shows Japan has already been dealing with record July heat, which keeps the upside tail alive even if the base case remains below the settlement thresholds.[7][15]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in Tokyo on July 31? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Who Will Win 2026, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

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 Who Will Win 2026. 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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Who Will Win 2026 trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.