Highest temperature in NYC on July 10?

Platform comparison

Market context

New York City is currently enduring an unprecedented July 2026 heatwave that has shattered records across the East Coast, with LaGuardia Airport hitting 104°F on 3 July, breaking a 60-year record by three degrees[1]. This extreme event frames the current 0% crowd-implied probability for a high temperature on 10 July, as traders recognise that while the heatwave is historic, the specific date falls outside the immediate peak of the recorded surge. Historical data shows LaGuardia’s absolute highest temperature is 103°F in August 1948, with July peaks previously capped at 101°F until this week’s anomaly[1][4].

Traders comparing Polymarket against Kalshi, Betfair, or Smarkets should note how these platforms diverge on weather volatility: Polymarket uses implied probability (0% YES here) while Kalshi lists decimal odds, and fee structures vary significantly between the KYC-heavy US books and offshore alternatives[3]. The primary catalyst to watch is the National Weather Service’s hourly forecast updates for the NYC metro area, as the current heatwave’s persistence depends on high-pressure system stability[6]. Recent reports confirm Newark and LaGuardia both hit 104°F on 3 July, suggesting the atmosphere remains primed for extreme readings, though the 10 July settlement window requires sustained heat beyond the current holiday-week peak[1][8].

The resolution source is Weather Underground’s daily high for LaGuardia (KLGA), a metric Polymarket users can verify directly against Kalshi’s official data feeds[3]. Unlike Betfair’s spread-based weather markets, Polymarket’s binary structure on this event offers a stark contrast in risk exposure, particularly given the 0% probability implying near-certainty of a lower temperature range[1]. Traders must monitor whether the heatwave extends into the weekend, as the 10 July high could still breach 95°F if the pressure system remains stationary, despite the current market pricing.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We read Highest temperature in NYC on July 10? from four platform perspectives: Polymarket (on-chain CLOB), Kalshi (CFTC-regulated exchange), Betfair Exchange (sports book exchange), Smarkets (peer-to-peer betting exchange). Polymarket's live mid is the canonical probability; the side-by-side columns benchmark fees, KYC, settlement currency and deposit rails so you can choose the venue that fits your jurisdiction and trade size.

Resolution & payout

Settlement is the biggest difference between the four platforms: Polymarket on-chain in USDC (instant), Kalshi USD via CFTC (T+1), Betfair and Smarkets in local currency via bank withdrawal (T+1 to T+3). On-chain settlement clears in minutes — the fastest payout path of the four.

FAQ

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.

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.