Highest temperature in NYC on July 20?

Platform comparison

Market context

The market bets on the peak Fahrenheit reading at LaGuardia Airport for 20 July 2026, with settlement tied to Wunderground’s daily high. Current crowd-implied probability sits at 0% for the “YES” outcome, yet Polymarket data shows the frontrunner outcome “82–83°F” commanding 100% probability, revealing a stark divergence between the binary implied probability and the range-specific consensus [1]. This mismatch suggests the binary contract may be mispriced relative to the underlying distribution, as traders overwhelmingly expect temperatures in the low 80s rather than extreme heat or cold.

Historical July peaks in NYC typically cluster between 78°F and 86°F, with 82–83°F representing a common median rather than an outlier. The 0% binary probability conflicts with this norm, implying either a structural error in the market’s binary framing or a temporary liquidity gap that distorts implied odds [1][2]. Comparable cases from recent summers show similar mid-80s highs, reinforcing that the 82–83°F range is the statistically anchored expectation rather than a speculative stretch.

Traders should monitor the National Weather Service’s 7-day forecast for the Northeast, which updates daily and flags heat advisories or marine influences that could shift LaGuardia’s peak. A sudden shift in the jet stream or an incoming coastal front could alter the day’s high by several degrees, making the 82–83°F range vulnerable to revision. No major announcements are scheduled before settlement, but real-time Wunderground updates on 20 July will be the definitive catalyst for resolution [2].

Sources: 1 · 2

Methodology

We track Highest temperature in NYC on July 20? 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

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.

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.