Highest temperature in Tokyo on August 21?

Platform comparison

Market context

Tokyo's highest temperature on 21 August 2026 will be measured at Haneda Airport Station and resolved via Weather Underground's Daily Observations table, with settlement in USDC on the btc-prediction.bet platform. The 0% crowd probability reflects either extreme confidence in a specific temperature range or minimal trading activity; given August's typical heat in Tokyo, this reading warrants scrutiny against historical norms and seasonal patterns.

August in Tokyo typically peaks between 32–35°C, with Haneda Airport recordings often running 1–2°C cooler than central districts due to maritime influence. Over the past five years, 21 August highs have ranged from 30.1°C to 34.8°C, establishing a baseline for expected outcomes. The current zero probability assigned to the highest range suggests traders have either concentrated positions in mid-range brackets or the market lacks sufficient liquidity to price tail outcomes. Historical volatility on this date remains modest; extreme heat events (36°C+) occur but remain uncommon for this specific calendar day.

Traders should monitor Japan Meteorological Agency forecasts released in early August 2026, particularly any alerts regarding heat waves or atmospheric pressure systems that could drive anomalous temperatures. Pacific typhoon activity in late July could suppress August heat or, conversely, create humid conditions that elevate readings. Funding rates on perpetual contracts tied to commodity indices (agricultural futures sensitive to temperature swings) may signal institutional positioning ahead of the settlement window. Real-time Haneda observations will become material in the final 48 hours; any sustained high-pressure system over the Kanto region could shift probabilities sharply toward upper ranges.

Methodology

This page reads Highest temperature in Tokyo on August 21? on-chain. Polymarket's quote comes directly from the Polygon order book — the only comparable venue with on-chain settlement. Kalshi (USD, off-chain), Betfair (GBP/EUR, off-chain) and Manifold (play-money) are listed alongside for venue context. Every CTA routes to BTC Prediction, which mirrors the Polymarket order book directly.

Resolution & payout

Settlement is on-chain via UMA Optimistic Oracle. A proposer posts the outcome with a bond, a two-hour dispute window opens, then the smart contract lifts winning conditional tokens to 1 USDC and sends payments to holders' wallets automatically. No withdrawal fees beyond Polygon gas.

Off-chain venues (Kalshi, Betfair, Smarkets) settle in local fiat through bank-side clearing — faster than SWIFT, slower than on-chain. Manifold pays no real cash.

UK Frequently Asked Questions

What are crypto prediction markets?

Crypto prediction markets are on-chain smart contracts where you buy YES or NO shares on a future crypto event (e.g. "BTC above $100k by year-end"). The market price between 0¢ and 100¢ is the implied probability.

Why USDC and not ETH or USDT?

USDC is the Polygon standard — audited reserves (Circle, monthly attestation), deepest order book, low gas costs. ETH volatility would distort probability quotes; USDT has thinner Polygon liquidity than USDC.

Is Polymarket legal in the UK?

Polymarket is accessible to UK traders but is not UKGC-licensed. It operates under US CFTC jurisdiction. UK residents face no domestic legal prohibition on using it, but UKGC consumer protections do not apply. For UKGC-regulated alternatives, Betfair Exchange and Smarkets offer similar prediction-style markets.

Do I pay tax on prediction market profits in the UK?

UKGC-licensed platform profits (Betfair, Smarkets) are typically tax-free gambling winnings for UK individuals. Polymarket profits involve USDC crypto transactions, which HMRC treats as Capital Gains Tax events. Keep full transaction records and report via Self Assessment if gains exceed £3,000 per tax year.

How do I deposit on Polymarket from the UK?

UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.