Highest temperature in NYC on August 14?

Platform comparison

Market context

New York’s 14 August heat story has shifted towards a slightly hotter and clearer midday set-up, with LaGuardia forecasts clustering around the mid-80s Fahrenheit and some outlets pushing the afternoon high to 86–88°F, while skies stay partly sunny and the air is described as less humid or hazy from distant wildfire smoke.[6][9][12] That keeps the market anchored to whether the airport’s highest daily reading lands in the upper 80s rather than merely the mid-80s, which matters because the contract settles from the Daily Observations table at Weather Underground, not the headline day-high summary.

Historically, late-summer LaGuardia readings in New York tend to sit near the upper 70s to upper 80s, so a current 0% YES implies the market is pricing almost no chance of an extreme outturn and only a narrow path to a higher bracket.[2][13] Recent similar forecast language has been consistent with ordinary August warmth rather than a deep heatwave, though the NWS did have a Heat Advisory for the wider metro earlier in the month, showing how quickly the city can move from benign to oppressive when humidity and sunshine line up.[7]

The key catalyst is the afternoon evolution at LaGuardia: cloud cover, sea-breeze influence, and any smoke-related reduction in solar heating will decide whether the station tops out near 84–86°F or reaches 88°F and above.[6][12] Traders should also watch for any updated airport observations through the late afternoon and early evening, because a later peak would still count if it appears in the Daily Observations table before the settlement window closes.[10][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

Where can I trade this market with the lowest fees?

Polymarket is geo-blocked in the US/UK/EU. The easiest 0%-fee broker into the same order book is Prediction Today. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

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%.