Highest temperature in NYC on July 27?

Platform comparison

Market context

New York City's peak temperature on 27 July 2026 will be measured at LaGuardia Airport and resolved against historical weather data from Wunderground. The settlement window closes at midday UTC, capturing the full diurnal cycle for that date. Current crowd-implied probability sits at 0%, suggesting either extreme confidence in a specific temperature range or minimal trading activity on this contract.

July temperatures at LaGuardia typically peak between 82–88°F, with historical July averages around 79°F and occasional heat waves pushing into the low 90s. The 30-year normal high for late July is approximately 84°F. Extreme readings above 95°F occur roughly once per decade during summer months; readings below 75°F are uncommon but possible during cooler-than-average patterns. The 0% probability reading diverges sharply from baseline climatological expectations, suggesting either the market has resolved to a single outcome or lacks sufficient liquidity to establish meaningful odds across temperature bands.

Traders should monitor National Weather Service forecasts and medium-range models from late June onwards, as July 2026 atmospheric patterns remain unknowable at present. Atlantic hurricane activity, jet-stream positioning, and high-pressure systems over the Northeast will determine whether conditions favour typical summer heat, anomalous warmth, or cooler-than-normal temperatures. Historical precedent shows that 10–14 day forecasts become reliable only within the final week before settlement, making early positions speculative against incomplete information.

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.

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.

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 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.