Highest temperature in Miami on August 5?

Platform comparison

Market context

Miami’s high temperature on 5 August will be judged against the Miami International Airport station, and the current 0% YES crowd price looks notably cautious against the live weather setup. Independent forecasts were clustered in the upper 80s to low 90s Fahrenheit: AccuWeather showed Miami’s early-August highs around 87-89°F[1], CBS News Miami forecast about 90°F with heat indices in the 100s[2], while one market venue showed the most-traded temperature bands centred on 84-89°F, with 90-91°F and 92-93°F still drawing meaningful volume[4]. That mix suggests the crowd is not pricing a true cool-day outcome, but rather a modest ceiling on the airport station reading.

Historically, Miami in August is defined by persistent heat rather than outlier spikes, so the key question is not whether it gets hot, but whether cloud cover, sea breeze timing, or showers cap the airport high below the upper-80s band. Forecast services for 5 August leaned hot and humid, with one Spanish-language preview calling for a peak near 91.6°F[5], although another source showed a rain-affected 31°C/88°F day[3]. For a contract tied to the single highest recorded temperature at KMIA, the practical comparison is between a low-90s airport maximum and a mid-to-high-80s finish, which is the range where most of the cross-platform disagreement sits.

Traders should watch the short-term forecast updates from National Weather Service Miami products and late-day convective timing, because in South Florida the airport maximum can be determined by whether storms arrive before or after the daily peak. The NWS Miami climate and record-report pages are the closest official references in the source set for local temperature validation[10][11], while the market venue itself shows active interest in several adjacent bins rather than a unanimous consensus[4]. The main catalyst is therefore not a policy or schedule announcement, but the intraday weather evolution that determines whether the final print lands in the 86-87°F, 88-89°F, or 90-91°F range.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

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.

UK Frequently Asked Questions

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 UK trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

What are the best prediction markets for UK traders in 2026?

For UKGC-regulated markets: Betfair Exchange (sports, politics) and Smarkets (sports, politics, lower commission than Betfair). For broader global event prediction: Polymarket (deepest liquidity, 0% fee, USDC settlement). For US-regulated option: Kalshi (USD, limited UK payment options). Most serious UK traders use a combination of Betfair for regulated sports and Polymarket for broader markets.