Highest temperature in Tokyo on August 21?

Platform comparison

Market context

Tokyo's maximum temperature on 21 August 2026 will be measured at Haneda Airport Station and recorded in Weather Underground's Daily Observations table. The settlement window closes at noon UTC on that date, capturing the highest reading from the previous 24 hours. Current crowd pricing reflects 0% implied probability, suggesting traders view the specific temperature range as unlikely or the market structure itself as presenting unfavourable odds relative to expected outcomes.

August represents Tokyo's peak summer season, with historical daily highs typically ranging between 32–35°C. The Japan Meteorological Agency's 30-year climate normals for mid-August show average maximum temperatures near 33°C, though individual days frequently exceed 36°C during heat waves. Comparable August dates from recent years—including the 2023 heat dome that pushed Tokyo to 37.9°C—demonstrate the volatility inherent in seasonal forecasting. The 0% crowd probability suggests either extreme confidence in a narrow temperature band or structural issues with how the market has framed its resolution ranges.

Traders monitoring this contract should track the Japan Meteorological Agency's monthly outlooks, typically released around mid-July, which flag above-normal or below-normal temperature probabilities for the following month. Pacific high-pressure systems and tropical cyclone activity in late July will shape August conditions. Weather Underground's data quality at Haneda—one of Japan's most reliably recorded stations—minimises resolution ambiguity, though the explicit reliance on Daily Observations rather than Day High & Low summaries requires verification of the platform's data hierarchy before settlement.

Methodology

We track Highest temperature in Tokyo on August 21? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

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?

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.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Best Prediction Markets 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.