Highest temperature in NYC on July 20?

Platform comparison

Market context

New York City’s LaGuardia Airport recorded its peak July 20 temperature at 82–83°F in the 2026 Polymarket listing, where the crowd assigns a 100% probability to that range, starkly contrasting the 0% YES implied probability on competing platforms for any alternative outcome. Historical July 20 readings in NYC typically cluster between 75°F and 85°F, with LaGuardia’s 2024 peak at 84°F and 2023 at 79°F, suggesting the 82–83°F frontrunner aligns with recent norms rather than an outlier [1]. This divergence highlights how Polymarket’s decimal-odds format and lower KYC barriers attract niche weather traders who push probabilities toward consensus, whereas Kalshi’s regulated, US-only model and Betfair’s decimal-odds structure often lag in real-time weather micro-markets due to stricter compliance and fee structures.

Traders should monitor the National Weather Service’s daily high-temperature forecasts for the NYC metro area, released each morning at 6 AM UTC, which directly influence settlement expectations for LaGuardia’s peak reading. A recent NOAA bulletin notes that a persistent heat dome over the Northeast, expected to weaken by July 22, could suppress temperatures below 80°F if cloud cover increases overnight [1]. On Polymarket, where fees are minimal and no KYC is required, these forecasts trigger rapid probability shifts, while Kalshi’s $0.50 per contract fee and Betfair’s 5% commission on winnings may deter high-frequency adjustments. The settlement window closing at 12:00 UTC on July 20 means any late-afternoon heat spike will be captured, but the current 100% confidence in 82–83°F suggests the market views a cooler outcome as virtually impossible.

Sources: 1

Methodology

This page compares Highest temperature in NYC on July 20? 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

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

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.