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, with the market resolving to whichever temperature band captures the highest reading that day. The settlement window closes at midday UTC, meaning traders must account for the full calendar day's heat before final resolution.

August in Tokyo typically sees daily highs between 32–35°C, with extreme heat events pushing readings above 37°C occurring roughly once per decade during the month. Historical data from the Japan Meteorological Agency shows that peak August temperatures at Haneda have reached 38.4°C (2013) and 37.8°C (2019), establishing a baseline for what constitutes an outlier reading. The current 0% crowd probability suggests the market may be pricing in a specific temperature threshold that historical August patterns rarely exceed, or traders are treating this as a calibration exercise given the two-year forecast horizon.

The Japan Meteorological Agency issues seasonal forecasts in early August that typically refine expectations for late-month weather patterns, including heat wave probability and upper-air conditions. El Niño or La Niña phases influence Pacific pressure systems affecting Tokyo's summer temperatures; the agency's most recent seasonal outlook should be consulted closer to August 2026. Traders should monitor any official heat-wave alerts issued by Tokyo metropolitan authorities in the days preceding 21 August, as these correlate with sustained high-pressure systems that drive maximum temperatures upward. The specific reliance on Haneda Airport's station data—rather than urban central Tokyo readings—matters, as airport locations sometimes record marginally different extremes depending on local wind exposure and surface characteristics.

Methodology

This page reviews Highest temperature in Tokyo on August 21? 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 Kalshi vs Polymarket, which mirrors the Polymarket order book at 0% fees.

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

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 Kalshi vs Polymarket. 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.

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.