Highest temperature in Tokyo on July 9?

Platform comparison

Market context

Tokyo’s July 9 high is expected to hit 30°C under sunny skies, with Met Office forecasts updated just 48 hours ago confirming above-normal warmth for the Haneda Airport station[4]. This sharp 24-hour shift in short-range models has pushed the 30°C outcome to 97% implied probability on Polymarket, while the 0% YES crowd-implied view for lower bands now appears misaligned with fresh data[1].

Historical July patterns in Tokyo show daily highs clustering between 29°C and 33°C, with the first half of the month averaging near 30°C[7]. The 29°C outcome still holds 31.5% probability on Lines.com, reflecting a fragmented eleven-way market where no single band commands majority support[3]. Yet the 1.5% hourly surge in 29°C pricing suggests forecast convergence, even as 30°C remains the frontrunner[3].

Traders should monitor the Japan Meteorological Agency’s 17:00 UTC daily update issued today, which currently cites a maximum of 29.6°C[8]. Any deviation above this threshold—especially if cloud cover clears by afternoon—could validate the 30°C outcome. Watch for real-time Wunderground readings at RJTT, as the contract resolves strictly on the official daily high recorded there[3].

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

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

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.

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.