Highest temperature in NYC on August 18?

Platform comparison

Market context

New York City's weather on 18 August 2026 will determine whether the day's peak temperature at LaGuardia Airport reaches into the upper 80s Fahrenheit or climbs higher. The 1% crowd probability reflects expectation of a relatively moderate summer day, though August in New York typically brings sustained heat. Current atmospheric patterns and seasonal trends will shape whether conditions align with typical late-summer conditions or deviate toward extremes.

Historical August temperatures at LaGuardia show the airport regularly records highs between 82–86°F during mid-month, with readings above 90°F occurring in roughly one-third of years. The 1% probability suggests traders are pricing in a scenario where the day falls notably cooler than the seasonal median or, conversely, significantly warmer than typical—either outcome representing statistical outliers. August 2024 saw LaGuardia reach 88°F on the 18th, whilst August 2023 peaked at 85°F the same date, providing recent benchmarks for what "normal" looks like.

Traders monitoring this market should track National Weather Service forecasts released in the week preceding 18 August, particularly any alerts regarding heat domes or Atlantic systems that could drive temperatures substantially above or below the 82–86°F range. Longer-range climate models from late July will offer early signals about whether North American pressure patterns favour anomalous warmth or cooler-than-average conditions. The resolution source—Weather Underground's Daily Observations table at LaGuardia—will be the definitive measure, not summary forecasts or other stations.

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.

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%.