Highest temperature in Miami on August 25?

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Market context

Miami is sitting in a familiar late-August pattern of heat, humidity and convective showers, with the National Weather Service flagging afternoon peaks in the low to mid 90s and scattered storms that can arrive late enough to leave the day’s high close to the early-afternoon reading[2][4]. At Miami International Airport, temperatures had already reached 90°F by 11 AM and 86°F at noon on 25 August, with the broader 24-hour window showing 91°F in the prior day’s observations[7]. That leaves the settlement range sensitive to whether the airport can edge above the low 90s before showers or onshore flow cap the afternoon.

The market’s 0% YES price implies the crowd sees the upper tail as effectively closed off, even though forecasters still allowed some upside risk. One NWS discussion from the previous day put the mean high near 97 and gave roughly a 10% chance of 100°F at the airport, while the current airport forecast matrix still centred Miami around 92–93°F for the day[6][8]. In comparable hot-season setups, the key read is not the daily high advertised for the city, but the exact Miami Intl Airport hourly trace: a brief burst of sun and a delayed storm can lift the contract, while an early shower or marine breeze can freeze the maximum below expectations.

For traders, the main catalysts are the timing of showers, the evolution of the easterly/southeasterly flow, and any storm that reaches the airport before local peak heating[1][4][5]. Settlement is determined by NOAA hourly data at KMIA, so the relevant mechanic is the highest reading in the “Temp” column, not the forecast high or heat index[7]. On the crypto side, any broader risk move that shifts BTC and ETH sentiment is secondary here; the contract is effectively a pure weather binary, margined and settled in USDC, with the main edge coming from local meteorology rather than exchange funding or whale flow.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reads Highest temperature in Miami on August 25? 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%.