Highest temperature in Miami on August 5?

Platform comparison

Market context

The outcome will be determined by the highest reading at Miami International Airport on 5 August, and the market is currently pricing a near-zero chance of the very hottest bands, with 0% implied for the broader long-shot view in your prompt. On Polymarket, the crowd is instead clustered around the low-to-mid 80s and upper 80s Fahrenheit, with several adjacent bands priced in the mid-range rather than the extreme tail.[2] That matters for comparison purposes because sportsbook-style climatological lines and weather-model forecasts generally point to a hot but not exceptional afternoon, which leaves little room for a surprise into the 90s unless cloud cover clears more aggressively than expected.[1][5][6]

Historically, Miami in August usually sits in a narrow hot-and-humid envelope rather than at the top end of the temperature distribution, so traders tend to read these contracts as a test of whether the day reaches the upper 80s rather than the low 90s.[3][17] AccuWeather’s August outlook for Miami shows daily highs mostly in the 87–89°F range, while CBS News Miami quoted a forecast high of around 90°F for the same date, which sits above the current crowd’s favoured mid-80s outcomes on Polymarket.[1][5] That gap between forecast guidance and market pricing is the key comparison point: prediction-market participants appear more cautious than the broadcast-weather view, while sportsbook-style weather products would typically track the same broad temperature envelope rather than implying a dramatic upside tail.[2][5][8]

For traders, the main catalysts are the daytime forecast updates, any shift in rainfall timing, and the official station observation at Miami International Airport, since the market resolves to the day’s highest recorded temperature there.[9][12] A hotter outcome usually requires stronger sun and delayed convection; a cooler one is more likely if showers or thunderstorms arrive earlier and cap the daytime high, which is consistent with some local forecast products showing rain risk or lower highs for the area.[4][11] Because the contract window ends at 12:00 UTC and the source is a specific airport station rather than a citywide average, late-afternoon changes in cloud cover or storm coverage are the practical dependency to watch.[9][15]

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reviews Highest temperature in Miami on August 5? 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 Best Prediction Markets, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

FAQ

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.

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.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Best Prediction Markets trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

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.