Highest temperature in NYC on July 21?

Platform comparison

Market context

On 21 July 2026, the highest temperature recorded at LaGuardia Airport will fall into one of several defined ranges. The National Weather Service maintains continuous records at this station, which serves as the official measurement point for New York City's daily extremes. The settlement hinges on Wunderground's historical data archive for that specific date, making the resolution mechanism transparent but dependent on a third-party weather database rather than real-time NWS feeds.

July temperatures in New York typically peak between 85–92°F, with historical records showing the city rarely exceeds 95°F during mid-summer. The 0% crowd probability suggests traders are either awaiting range options to be displayed or treating this as a placeholder market. On Kalshi, weather markets often show tighter spreads than Polymarket equivalents because Kalshi's regulatory framework allows US-domiciled traders direct access without KYC friction for lower-stake positions. Betfair's decimal odds format can obscure implied probabilities for casual traders unfamiliar with converting 1.01 to 99% likelihood, whereas Smarkets displays probabilities directly. The fee structure varies materially: Kalshi charges a flat commission on winnings, whilst Polymarket's Polygon-based settlement typically incurs lower transaction costs but requires wallet setup.

The Atlantic hurricane season peaks in August and September, so early-July weather patterns remain driven by typical summer high-pressure systems rather than tropical disturbances. Long-range forecasts from NOAA become more reliable within 10–14 days of the settlement date. Traders should monitor early-July 2026 heat dome developments and any anomalous jet-stream positioning that might drive sustained heat into the Northeast.

Methodology

We read Highest temperature in NYC on July 21? 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.

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 UK has a different geo footprint and routes to Polymarket's order book at 0% fees.

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.

Which platform supports Klarna/SOFORT?

Directly: none. Polymarket accepts only USDC on Polygon. Kalshi Alternative UK 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.