Highest temperature in NYC on July 17?

Platform comparison

Market context

The market tracks the peak Fahrenheit temperature recorded at LaGuardia Airport on 17 July 2026, resolving via Wunderground’s daily history for station KLGA. With settlement fixed at 12:00 UTC on the event date, the current 0% implied probability for any specific range appears inconsistent with the distribution shown on Polymarket, where 86–87°F holds 35% and 88–89°F holds 30% [1]. This divergence suggests either a data feed lag or a misalignment between the user interface and the underlying order book, a common friction point for automated traders relying on real-time probability streams.

Historically, mid-July highs at KLGA cluster between 84°F and 92°F, with 86–89°F representing the median band over the past decade. The 0% figure for all outcomes contradicts this empirical baseline, as even conservative models assign non-zero probability to the leading ranges. Programmatic approaches should treat this as an arbitrage signal: scripts polling the API must validate whether the 0% reflects a true null state or a transient sync error before executing conditional orders.

Traders should monitor the National Weather Service’s 7-day forecast for the New York area, particularly the heat index and dew point trends issued daily at 12:00 UTC, as these directly influence peak temperature resolution [2]. No specific announcements are pending, but dependencies include Wunderground’s data ingestion latency and the NWS’s official observation time, which can shift the recorded maximum if the peak occurs near the 12:00 UTC settlement cutoff.

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

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

FAQ

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 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.