Highest temperature in Tokyo on August 4?

Platform comparison

Market context

Tokyo’s highest temperature at Haneda Airport on 4 August is a straight weather bet, and the current 0% YES price is hard to reconcile with the climatology and the live forecast. Tokyo’s August average high is around 31–31.1°C, with AccuWeather showing 4 August at roughly 85°F/29.4°C and broader August highs clustered in the low 30s Celsius; the Japan Meteorological Agency’s Tokyo-area daily data also shows first-August maxima already in the mid-30s at some Tokyo stations, underscoring how easily the region can reach or exceed the upper-20s to low-30s range on a summer day.[1][9][10][16]

For comparable cases, traders normally anchor to the distribution of late-summer Tokyo temperatures rather than a single forecast snapshot. Historical and forecast services consistently place August in Tokyo as hot and humid, with typical daytime maxima around 30–31°C and rainfall frequent enough to cap extremes on some days, but not enough to remove heat risk altogether.[3][8][17] Against that backdrop, a 0% implied probability looks like either a stale market, a data issue, or an overreaction to a cooler early-morning reading; on a contract settled to the day’s maximum at Haneda, anything from the high 20s into the low 30s Celsius remains plausibly live if sunshine develops later.[2][13]

The main catalysts are the day’s evolving forecast, any rain bands passing over Kanto, and the timing of afternoon heating, which matters more than the early UTC-morning observation window. Live hourly guidance already shows Tokyo warming through the morning into the 80s Fahrenheit, and seasonal August forecasts continue to point to heat with intermittent showers rather than a sustained cool spell.[2][1][16] For cross-platform comparison, sportsbook-style weather derivatives and forecast-market pricing would typically converge only if the intraday forecast collapses towards a lower ceiling; absent that, prediction-market pricing near zero is materially below what the weather outlook implies.[1][2][16]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page is a comparison snapshot: one live quote, four reference venues with their key attributes, and a single execution path — every trade button routes to PolyGram, which mirrors the Polymarket order book directly.

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

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.

Do I need to KYC for this market?

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

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.