Highest temperature in Miami on August 5?

Platform comparison

Market context

Polymarket is pricing this contract at **0% YES** today, so the market is effectively saying there is no live expectation of a qualifying Miami high reaching the relevant bracket on the settlement date. Because this is a USDC-settled, Polygon-based conditional token market, the price is the cleanest read on current trader consensus rather than a forecast of the weather itself; with the final outcome tied to the Miami Intl Airport Station at Weather Underground, the key question is where the day’s *maximum* ends up once the station’s full daily record is complete.[8]

That 0% print sits against a July-to-August Miami pattern that is normally hot enough to keep high-temperature outcomes clustered in the upper 80s and low 90s Fahrenheit. AccuWeather’s August page shows recent daily highs around 87–89°F, while CBS Miami’s forecast for 5 August 2026 called for a high near 90°F, consistent with the city’s late-summer baseline rather than an extreme outlier.[1][4] A recent local record report also showed Miami International Airport hitting 96°F on consecutive days in early August 2026, underscoring that the upper end of the distribution can still be reached when heat builds over South Florida.[9]

For traders, the main catalysts are the day-of forecast updates, any shift in cloud cover or rain timing, and whether the airport station logs its peak before convective storms or sea-breeze changeovers cool the afternoon. On this market, the practical watchpoints are the Weather Underground history page for KMIA, National Weather Service updates, and any late-breaking South Florida forecast revisions that change the expected high by a degree or two; those are what can move the implied probability away from zero on a conditional token priced in USDC on Polygon.[8][13][15]

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.

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%.