Highest temperature in NYC on May 30?

Platform comparison

Active sub-markets

Market context

On 30 May 2026, the highest temperature recorded at LaGuardia Airport will fall into one of several defined ranges. The settlement mechanism relies on historical weather data from Weather Underground, making this a straightforward instrumental reading rather than a forecast-dependent outcome. The 0% crowd probability suggests either extreme confidence in a specific temperature band or sparse liquidity on alternative outcomes—a signal worth examining against seasonal norms and platform-specific trading patterns.

New York's late May temperatures typically peak between 75°F and 85°F, with historical highs occasionally reaching into the low 90s during heat waves. May 2024 saw a high of 84°F on the 30th; May 2023 recorded 79°F. These precedents establish a baseline against which current market odds can be calibrated. Kalshi and Betfair often show tighter spreads on weather markets than Polymarket due to their institutional participation, whilst Smarkets' decimal odds format can obscure whether the 0% reading reflects genuine consensus or thin order books. The absence of competing probability estimates across platforms suggests this particular temperature band may be undertraded rather than definitively mispriced.

Traders should monitor National Weather Service seasonal forecasts released in late April and early May, which typically narrow confidence intervals for specific dates. El Niño or La Niña patterns, if active in spring 2026, could shift May temperature distributions measurably. No scheduled weather events or infrastructure changes at LaGuardia are anticipated to alter measurement conditions. The settlement window closes at midday UTC, creating a brief window for same-day arbitrage if morning temperatures diverge sharply from overnight expectations.

Methodology

We read Highest temperature in NYC on May 30? 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 quote comes directly from the Polygon order book; the other three are listed with their platform attributes — fees, KYC, settlement currency, payment options — because a 1:1 contract comparison without API access would be guesswork.

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

Where can I trade this market with the lowest fees?

On Polymarket Alternative, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

Polymarket Alternative is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.