Highest temperature in Tokyo on August 10?

Platform comparison

Market context

The key variable is the **highest observed temperature at Tokyo Haneda Airport Station** during the observation day, not the headline forecast high, so traders should model the market off intraday station data rather than city-wide summaries. At 06:03 local time, Tokyo was already **77°F** (about **25°C**), with AccuWeather showing a **90°F/72°F** day range for 10 August and Weather Underground’s settlement logic pointing to the Daily Observations table as the final source of truth.[3][5]

The current **0% YES** implies the crowd sees the listed outcome range as effectively impossible, but August climatology in Tokyo argues against treating that as informative by itself: August is typically the hottest month, with average highs around **31°C** and common daily ranges in the upper 20s to low 30s Celsius.[8][12] Comparable recent heat episodes in Japan also matter because they show how quickly forecasts can undershoot realised maxima when the Pacific summer pattern strengthens; the Japan Meteorological Agency recorded extreme heat across the country in early August, with national headlines focused on record-breaking temperatures and heat-risk advisories.[9][14]

For a hands-on trader, the practical checklist is straightforward: watch the local forecast updates, then monitor the live station observations through the afternoon because the resolving value is the maximum printed in the hourly/daily log, not the summary panel.[5] Programmatically, the clean approach is to poll the source page for the Tokyo Haneda Airport Station record, cache the highest timestamped Celsius reading, and keep updating until the next day’s first datapoint appears, since later revisions can still change the final number inside the settlement window.[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

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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 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.