Highest temperature in NYC on August 9?

Platform comparison

Market context

LaGuardia Airport is the reference station for settlement, and the crowd is effectively pricing an outcome in the **90–91°F** band as near-certain, with Polymarket showing that range at **100%** while a rival market view has the contract at **0% YES** overall. That gap matters because the contract is not resolving off a generic NYC high, but off the highest value in Weather Underground’s LaGuardia daily observations table, so the practical question is whether the final logged maximum lands inside the specified range rather than whether the day felt broadly hot across the city.[4][5]

Historically, late-summer New York City maxima often cluster in the upper 80s to low 90s, and recent comparable readings fit that pattern: WeatherSpark’s LaGuardia data showed **88.0°F** late on 9 August with a **89.1°F** six-hour high, while AccuWeather’s monthly page implied a forecast around **90°F** for that date.[1][2] The main market read-through is that a narrow temperature band can still resolve against traders if the station peak prints just above or below the listed range, so the absence of a wider cushion makes small differences in the logged maximum disproportionately important.[4][5]

For catalysts, traders should watch the timing of the final Weather Underground update for KLGA and any late revisions before the next day’s first datapoint, because the market rules allow revisions until that cutoff.[4] National Weather Service guidance for the New York area and LaGuardia remained consistent with a hot, mostly clear setup in the near-term forecast, which supports the existing consensus rather than undermining it.[12][10] The only meaningful divergence in cross-platform pricing is therefore not about direction, but about whether the settlement source records a number that sits inside the market’s favoured bracket.[4][5]

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.

FAQ

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 Best Prediction Markets. 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.

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.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.