Highest temperature in NYC on August 19?

Platform comparison

Market context

New York City's peak temperature on 19 August 2026 will be measured at LaGuardia Airport and resolved against specific temperature bands. The market currently shows 0% implied probability across all ranges, suggesting either extreme uncertainty or insufficient liquidity at current odds. Resolution hinges on the Daily Observations table from Weather Underground rather than summary figures, a technical distinction that matters when hourly readings diverge from day-high reporting.

August temperatures at LaGuardia historically cluster between 78°F and 88°F, with extremes rarely exceeding 95°F or dropping below 70°F. The 2023 peak for mid-August was 86°F; 2022 saw 84°F. These patterns anchor reasonable expectations, though the 0% crowd probability suggests traders may be awaiting clearer odds or testing platform mechanics. Kalshi's binary-style settlement differs from Polymarket's fractional odds presentation—the same underlying event reads differently across books depending on how ranges are bucketed and priced.

Traders should monitor National Weather Service forecasts beginning mid-August 2026, particularly heat advisories or tropical system activity that could shift temperatures materially. Atlantic hurricane season peaks in September but occasionally influences August weather. The settlement window closes at 12:00 UTC on 19 August, meaning afternoon readings after market close won't affect resolution. Fee structures vary across platforms—Kalshi charges 2% on winnings, whilst Polymarket's Matic-based fees differ—making small-margin weather trades more sensitive to venue selection than outright probability assessment.

Methodology

This page compares Highest temperature in NYC on August 19? specifically across Polymarket, Kalshi, Betfair Exchange and Smarkets. The live probability is the Polymarket mid; the comparison columns summarise each venue's fee structure, KYC, settlement currency and payment rails. Every CTA routes to Kalshi Alternative, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Polymarket settles via UMA Optimistic Oracle on Polygon. A proposer posts the outcome with a bond, the two-hour window runs, then the smart contract pays USDC.

Kalshi settles USD through the CFTC-regulated clearinghouse — the cleanest variant, with heavier KYC. Betfair Exchange settles in account currency (GBP/EUR), net of 2-5% commission. Smarkets follows the same model as Betfair with a lower default 2% commission.

FAQ

Polymarket vs Kalshi — which is better?

Depends on your location. Kalshi is CFTC-regulated, US-only with full KYC. Polymarket is global, on-chain, no KYC up to $1,500. Polymarket has ~10x higher liquidity but higher regulatory risk.

What does Polymarket cost vs Kalshi?

Polymarket: 0% fees, only Polygon network costs (~$0.01/trade). Kalshi: up to 7% per trade plus spread. For high-frequency traders, Polymarket is dramatically cheaper.

Which platform has the deepest liquidity?

Polymarket — by a wide margin. Top markets reach $50-500M volume, Kalshi ~$200M cumulative, Betfair similar. Deeper liquidity means your trade moves the quote less.

Is Betfair a Polymarket alternative?

Only partially. Betfair Exchange is UK-focused with a sports-betting emphasis; they have politics markets but with thinner liquidity than Polymarket. Settlement in GBP/EUR, 2-5% commission on winnings.

Are all these platforms regulated?

No. Kalshi is CFTC-regulated (US). Betfair and Smarkets are UK Gambling Commission licensed. Polymarket operates without explicit regulation — a different risk profile than a regulated sportsbook.