Highest temperature in NYC on July 4?

Platform comparison

Market context

On 4 July 2026, the highest temperature recorded at LaGuardia Airport will determine the outcome of a prediction market focused on New York City’s peak summer heat. The current crowd-implied probability of 0% for the “YES” outcome suggests traders believe the temperature will not exceed the specified threshold, despite recent historical extremes that challenge such certainty.

Historical data frames this probability with caution: LaGuardia has recorded 94°F at midnight just days ago, marking NYC’s warmest midnight ever, and hit 104°F earlier this year, surpassing the old record of 101°F. The all-time high for the station is 107°F, set on 3 July 1966 [8]. These cases indicate that July in NYC can produce extreme heat, making a 0% implied probability potentially fragile. Platforms diverge here: Polymarket uses decimal odds and lower fees with minimal KYC, while Kalshi and Betfair rely on implied probability, stricter identity checks, and higher fee structures, which may influence how each book prices this volatility.

Traders should monitor the National Weather Service’s daily forecasts for LaGuardia, which for July 2026 predict highs between 81°F and 99°F, with overnight lows from 68°F to 83°F [4]. A key catalyst is the upcoming heatwave schedule; Fox Weather recently reported NYC hitting 104°F, hotter than Phoenix, underscoring how rapidly conditions can shift [7]. Platforms like Smarkets and Betfair may adjust odds more slowly due to regulatory dependencies, whereas Polymarket’s decentralised model allows faster reaction to such news. Watching Wunderground’s real-time updates for LaGuardia will be critical as the settlement window closes on 4 July 2026 at 12:00 UTC.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page compares Highest temperature in NYC on July 4? 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 Polymarket Alternative, which mirrors the Polymarket order book at 0% fees.

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

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.

Which platform is accessible globally?

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