Highest temperature in NYC on August 19?

Platform comparison

Market context

New York City's peak temperature on 19 August 2026 will be determined by readings from LaGuardia Airport's official weather station, with resolution tied specifically to the Daily Observations table on Weather Underground rather than summary figures. This distinction matters operationally: automated systems querying the API must target the granular observation records, not the aggregated high-low display, to avoid settlement disputes. The market currently shows 0% implied probability across all temperature ranges, suggesting either insufficient liquidity or a data-loading issue rather than genuine consensus that no temperature will be recorded.

Historical August temperatures at LaGuardia cluster between 75–88°F for daily highs, with extreme readings above 95°F occurring roughly once per decade. The 2019 heat wave pushed readings to 96°F on 20 August; the 2022 summer saw multiple days exceed 90°F in mid-August. These precedents establish that mid-80s outcomes are modal, whilst ranges above 92°F represent tail events. A trader building conditional logic would weight seasonal normals heavily but flag any Atlantic tropical system activity as a volatility driver capable of suppressing temperatures below historical August means.

Monitoring should focus on National Weather Service forecasts issued 7–10 days prior to settlement, which typically narrow uncertainty bands. Late-August jet stream positioning determines whether cool Canadian air masses penetrate the Northeast; conversely, Bermuda high-pressure systems drive sustained heat. The settlement window closes at midday UTC on 19 August, creating a hard cutoff for live-market adjustments once morning observations are logged. Programmatic traders should establish data-refresh intervals aligned with Weather Underground's update cadence to capture intraday temperature peaks before market close.

Methodology

This page reviews Highest temperature in NYC on August 19? across five venues. The live probability is the Polymarket mid-price, sourced directly from the on-chain Polygon order book; the comparison columns benchmark each venue on fee structure, KYC, settlement currency and payment rails. Every CTA routes to Kalshi Fees, which mirrors the Polymarket order book at 0% fees.

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

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.

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.