Highest temperature in Tokyo on August 10?

Platform comparison

Market context

Tokyo’s settlement will depend on the **highest observed Celsius temperature at Haneda Airport**, not the summary “Day High & Low” figure, so the key question is the peak reading in the Weather Underground Daily Observations table during the settlement window. Tokyo is usually very warm in August: long-run climate references put typical August highs around 31°C, while recent historical August 10 readings have often landed in the low-to-mid 30s Celsius, with some years reaching 35°C or above.[3][4][13]

The current **0% YES** implies the market is pricing an outcome outside the relevant band or, more likely, treating the target range as effectively out of reach unless a late-day spike appears. Comparable Tokyo summer data show that extreme heat is common enough to keep a 35°C-plus print on the board, but not routine every day; in 2025, for example, Tokyo logged multiple 35°C-or-hotter days, underscoring how quickly the distribution can shift in a heatwave regime.[17] That makes the on-chain pricing sensitive to the exact bracket definitions, because a one-degree move can flip settlement across adjacent ranges and USDC is then paid out mechanically on the final resolved outcome.

Traders should watch for the afternoon local-time temperature peak, any convective shower or sea-breeze moderation, and whether Typhoon-adjacent weather alters the thermal ceiling. The main dependency is the Weather Underground station feed itself: if Haneda’s Daily Observations table prints a higher maximum than the summary section, the table controls resolution, which can matter when data sources diverge on the day’s official high.[3] On the crypto side, the market’s odds can also move with broad risk appetite in BTC and ETH if speculative flow lifts or cuts demand for small-balance weather contracts, but the settlement itself remains a simple USDC event tied to the final published reading.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically this overview focuses on on-chain pricing: Polymarket's live mid comes from the Polygon conditional-token order book and settles automatically in USDC. The other three venues — Kalshi, Betfair, Manifold — sit alongside as off-chain reference points so you can see how the contract translates across regulatory and settlement regimes.

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.

What does a transaction cost on Polygon?

Polygon gas is typically under $0.01 per transaction. A full trade cycle (Approve + Order + Fill) totals around $0.03 — compared to $5-50 on Ethereum mainnet.

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%.