Highest temperature in NYC on July 20?

Platform comparison

Market context

On 20 July 2026, LaGuardia Airport will record its peak daily temperature in degrees Fahrenheit, the sole metric determining settlement for this Polymarket contract. Today, the on-chain market prices the “YES” outcome at 0%, while the frontrunner range of 82–83°F commands a 100% implied probability, reflecting near-certainty among traders that the day will be warm but not extreme [1].

Historical July highs in New York City typically cluster between 78°F and 85°F, with LaGuardia often reading slightly cooler than Central Park due to its coastal exposure. The current 100% weighting on 82–83°F aligns with long-term averages for mid-July, where temperatures rarely dip below 75°F or exceed 90°F in recent decades. This stability explains the market’s dismissal of colder ranges like “69°F or below,” which sit at 0% [1].

Traders should monitor the National Weather Service’s 7-day forecast for the Northeast, particularly any updates on high-pressure systems or marine air intrusions that could suppress temperatures. A recent forecast from EaseWeather indicates July 2026 highs near 30°C (86°F) across New York, supporting the 82–83°F consensus [2]. Settlement relies on Wunderground’s recorded peak for KLGA, finalised when the Polygon-based conditional tokens resolve in USDC after 2026-07-20T12:00:00Z.

Sources: 1 · 2

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

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 PolyGram. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like PolyGram trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.

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.