Highest temperature in NYC on July 17?

Platform comparison

Market context

The market tracks the peak Fahrenheit reading at LaGuardia Airport on 17 July 2026, with the crowd currently assigning zero probability to any outcome exceeding the lowest bracket. Historical mid-July data shows LaGuardia frequently hits 86–94°F during heatwaves, including a record 94°F midnight reading in 2023 that broke a decade-old high [3]. On Polymarket, the frontrunner is 86–87°F at 35%, followed by 88–89°F at 30%, illustrating how fractional implied probabilities here diverge from Kalshi’s decimal odds or Betfair’s price-based liquidity [1]. While Polymarket operates with minimal KYC and variable fee tiers, Kalshi mandates full identity verification and standardises fees, creating distinct risk profiles for identical weather events.

Traders should monitor the National Weather Service’s July heat advisories and the timing of the East Coast heatwave, as LaGuardia’s records often lag Central Park by a degree or two during extreme spikes [2]. Recent reports confirm NYC hit 100°F in Central Park for the first time since 2012 on 3 July 2026, suggesting sustained thermal pressure that could push LaGuardia into the 90s if the wave persists [4]. Unlike Smarkets, which offers commission-based betting with no KYC for small stakes, Polymarket’s resolution relies solely on Wunderground’s daily max for KLGA, meaning any discrepancy between station readings could invalidate bets placed on alternative books that use different sources. The settlement window closes at 12:00 UTC on 17 July, locking in the final temperature range before resolution.

Sources: 1 · 2 · 3 · 4

Methodology

This page compares Highest temperature in NYC on July 17? 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

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.

What about Smarkets as an alternative?

Smarkets is a UK betting exchange with a lower default commission (2%) than Betfair. Liquidity on political markets is below Polymarket, comparable to Kalshi. Geo-blocked in many jurisdictions.

Which platform is accessible globally?

Polymarket is geo-blocked in the US/UK/EU. Kalshi is US-only. Betfair and Smarkets are UK-restricted. Kalshi Alternative has a different geo footprint and routes to Polymarket's order book at 0% fees.

Which platform supports Klarna/SOFORT?

Directly: none. Polymarket accepts only USDC on Polygon. Kalshi Alternative offers a fiat on-ramp via Klarna or SOFORT (DE/AT/CH) and converts internally to USDC for the Polymarket order book. T+1 processing.