Highest temperature in NYC on July 23?

Platform comparison

Market context

New York City’s hottest reading at LaGuardia on 23 July 2026 will settle on the day’s maximum observed temperature, with the market currently pointing most heavily to the **80–81°F** bucket rather than the upper 70s or mid-80s. Polymarket’s book shows that range as the clear front-runner at **72%**, with **82–83°F** next at **19%**[1]. That is a very different signal from the **0% YES** crowd-implied probability shown on the alternative framing here, which suggests the contract pricing may be reflecting platform-specific wording, range mapping, or a stale view of the event rather than a simple weather call.

For comparison, weather markets tend to be driven by the day’s actual forecast path more than by long-run seasonality: late July in New York is normally one of the warmest periods of the year, so anything near or above 80°F is not unusual, but small changes in cloud cover, wind direction, and sea-breeze timing can shift the final peak by several degrees. Recent coverage of the July 2026 heat wave noted that record-breaking temperatures were already affecting parts of the East Coast, underlining how quickly a summer pattern can push urban highs above expectations[2]. That matters here because the contract resolves to the **highest temperature recorded at LaGuardia**, not a citywide average, so airport-specific microclimate effects can decide the bucket.

On platform comparison, Polymarket shows the market in **implied probability** terms, whereas Kalshi and some sportsbooks present prices as contract value or decimal-style odds, which can make the same view look less or more extreme depending on the format. Betfair and Smarkets also add exchange-style fees and, in practice, tighter KYC and jurisdictional limits than a purely crypto-native venue, so the tradable audience can differ even when the headline view is the same. For a contract like this, the key check is whether each book is using the same resolution source and temperature banding, because a one-degree threshold can move value between adjacent outcomes.

Sources: 1 · 2

Methodology

This page compares Highest temperature in NYC on July 23? 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

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.

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