Highest temperature in NYC on July 21?

Platform comparison

Market context

On 21 July 2026, the highest temperature recorded at LaGuardia Airport Station will determine which range this market resolves to, with settlement occurring at 12:00 UTC that day. The current crowd-implied probability of 0% YES suggests either extreme confidence in a specific outcome or insufficient liquidity across available ranges. Wunderground's historical records serve as the authoritative resolution source, with temperature data pulled directly from the airport's official monitoring station.

New York City's July climate presents a relatively narrow band of plausible outcomes. Historical data from LaGuardia shows July highs typically cluster between 82–88°F, with extreme readings rarely exceeding 95°F or falling below 78°F. The record high for any July day at the airport stands at 104°F (set in 1966), though such outliers remain statistical anomalies. The 0% probability currently priced suggests traders have converged on a single temperature band as overwhelmingly likely, though this concentration of conviction warrants scrutiny given the inherent variability of summer weather systems.

Traders should monitor the National Weather Service's extended forecast as mid-July 2026 approaches, particularly tracking whether Atlantic high-pressure systems or tropical moisture patterns develop. Heat domes or unusual weather blocking patterns could shift outcomes materially from historical norms. The settlement window's noon UTC cutoff means the market resolves based on the full calendar day's peak temperature, not intraday volatility, reducing exposure to timing-based gaming but requiring traders to assess full-day meteorological conditions rather than isolated peak hours.

Methodology

We track Highest temperature in NYC on July 21? 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.

FAQ

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.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

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.