Highest temperature in NYC on August 9?

Platform comparison

Market context

The relevant real-world event is the maximum temperature recorded at LaGuardia Airport for 9 August, as logged in Weather Underground’s daily observations rather than the summary high/low box. For programme-style monitoring, the cleanest approach is to poll the station page late in the day, extract the highest value from the observations table, and keep watching for late revisions until the first datapoint for the next date appears, because the market rules allow changes up to that point.[4][12]

The present 0% crowd-implied chance on the yes side is best read as a near-certain lean against the event landing in the specified range, but weather markets can still reprice quickly if the observed peak moves with the afternoon heating cycle. The wider New York climatology for early August supports a warm but not extreme baseline: the National Weather Service’s climatological reporting for NYC shows an 87°F maximum on the prior day, while the Polymarket contract itself notes external consensus around a mid-90s-style outcome bucket for this event, showing how traders are typically anchored to official forecast guidance rather than the venue’s summary display.[1][4]

For catalysts, a trader should watch the latest forecast package, any short-term NWS or airport forecast updates, and the timing of the day’s last observation publication, since the settlement source is a specific station feed and not a generic city temperature. A practical bot setup would compare the live KLGA observations against the market’s bucket thresholds, trigger alerts when the realised high enters a neighbouring range, and avoid relying on headline weather app highs, which can differ from the station record used for settlement.[7][10][12]

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%.