Highest temperature in NYC on July 20?

Platform comparison

Market context

New York City’s highest temperature on 20 July 2026 will be recorded at LaGuardia Airport, with the market resolving to the Fahrenheit range containing that peak. The current crowd-implied probability for a “YES” outcome sits at 0%, yet Polymarket’s frontrunner is the 82–83°F band at 100% probability, revealing a stark divergence between the binary framing and the underlying temperature-range contract. This mismatch suggests traders are pricing a specific heat window while the binary market treats any non-confirmation as a loss, creating an arbitrage gap between platforms.

Historical July highs in NYC typically cluster between 75°F and 85°F, with LaGuardia often recording peaks near 82°F during stable summer conditions. The 0% YES probability appears inconsistent with this baseline, as even modest heatwaves routinely exceed 80°F. Comparable cases from July 2024 and 2025 show highs of 84°F and 81°F respectively, framing the current odds as an outlier that may reflect a mispriced binary structure rather than genuine cold expectations.

Traders should monitor the National Weather Service’s 7-day forecast for the Northeast, which updates daily and flags heat advisories that could push temperatures into the 82–83°F range. A recent forecast from EaseWeather indicates July 2026 highs near 30°C (86°F), reinforcing the likelihood of temperatures in the frontrunner band [2]. Watch for any sudden shifts in the 5-day model runs from NOAA, as a rapid cool-down would be the only catalyst to invalidate the 82–83°F consensus and justify the 0% YES line.

Sources: 1 · 2 · 3

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

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

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.

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.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Kalshi vs Polymarket 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.