Highest temperature in NYC on August 18?

Platform comparison

Market context

On 18 August 2026, the highest temperature recorded at LaGuardia Airport will determine this market's outcome. Polymarket currently prices the YES side at 1%, implying traders expect the daily high to fall below the threshold embedded in the contract's upper boundary. The market settles against Weather Underground's Daily Observations table rather than the Day High & Low summary, a distinction that matters when automated station readings diverge from human-reviewed figures—a common occurrence during extreme heat events when quality-control flags may delay official publication.

August in New York typically peaks between 82–86°F, with the historical 30-year average high around 82°F. The record for any August day at LaGuardia stands at 96°F (set in 1933), though readings above 95°F remain rare, occurring roughly once per decade. The 1% probability suggests the market has priced in a scenario requiring either an anomalous heat dome or a misalignment between the Daily Observations and Day High & Low tables—both low-probability events. Comparable August heat events in the Northeast have occasionally produced 90°F+ readings, but sustained extreme heat typically requires a blocking high-pressure system to persist for multiple days.

Traders should monitor the National Weather Service's extended forecast for late August 2025 onwards, particularly any signals of Atlantic hurricane activity or continental heat transport patterns. The NOAA Climate Prediction Center's monthly outlooks, published around the 15th of each preceding month, will provide early indication of whether August 2026 tracks toward anomalous warmth. Real-time tracking begins in earnest by mid-July 2026, when deterministic models gain reliable skill beyond ten days.

Methodology

We track Highest temperature in NYC on August 18? across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

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 Polymarket Scam?. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

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%.