Highest temperature in NYC on July 23?

Platform comparison

Market context

LaGuardia’s hottest reading on 23 July is currently priced by Polymarket as a modestly warm outcome, with the 80–81°F band leading at 72% and 82–83°F next at 19%.[1] For a trader, that means the contract is not pricing a major heat spike; it is instead centred on a fairly ordinary summer high for New York City, settled against the Wunderground record for LaGuardia Airport and paid out in USDC via conditional tokens on Polygon.

The current 0% YES implied probability appears at odds with the market’s own outcome ladder rather than with the meteorology itself.[1] In practice, this kind of contract is usually read as a distribution over afternoon heat at one station: if the day runs close to forecast, the 80s band can dominate; if cloud cover, marine air, or an earlier sea breeze limits warming, the market can migrate down a bracket. The relevant comparison is not “hot or cold” in general, but where the day’s maximum lands relative to the settlement bands used on-chain.

The main catalysts are the short-range forecast updates from the National Weather Service and any changes in convection, cloud cover, or wind direction that affect LaGuardia specifically, since airport temperatures can diverge from the rest of the city. A trader also needs to watch the Wunderground history page close to the settlement window, because the market resolves on the highest recorded temperature for the day at KLGA, not on an average or a citywide estimate. Heat alerts or thunderstorm timing matter most when they alter the afternoon peak, and even small forecast revisions can shift probability between adjacent temperature bands.[2]

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

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 PolyGram. 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 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.