Highest temperature in NYC on August 21?

Platform comparison

Market context

The underlying event is the LaGuardia Airport temperature reading used to settle the NYC August 21 contract, with the market tied to the highest value in the daily observations rather than any summary high shown elsewhere. The current 0% YES price implies traders see the outcome as already fixed or effectively priced, which is consistent with a market whose final reading hinges on a single station report rather than a citywide composite.

For context, late-August NYC temperatures often cluster in the upper 70s to low 80s when skies are mixed and winds are onshore, while brief heat surges can still push readings into the upper 80s or low 90s. Recent coverage of the month’s weather pointed to a hot, humid spell earlier in August, but the specific setup for 21 August was cooler, with forecasts and airport-based histories clustering around the high 70s rather than any extreme. That leaves the market leaning on routine late-summer conditions rather than a heat-wave tail risk.

The main catalyst to watch is the published LaGuardia daily observations sequence, especially whether the final pre-midnight entries or any later updates nudge the day’s maximum into a higher bracket before the settlement cut-off. Traders will also track any discrepancy between the Weather Underground daily table and the headline day-high summary, because the contract specification gives the table priority.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page tracks Highest temperature in NYC on August 21? across four political prediction venues. Live odds come from the Polymarket order book (the deepest political prediction-market book). Kalshi is the CFTC-regulated US alternative, Betfair the established UK sports-exchange with politics markets, Manifold the open play-money variant. For users geo-blocked from Polymarket directly, brokers like Trump Prediction provide a 0%-fee route into the same order book.

Resolution & payout

For political markets the resolution source is decisive. Polymarket defines a concrete source per contract (e.g. AP, Reuters, official electoral commission) and uses the UMA Optimistic Oracle as the on-chain dispute mechanism. With a clearly defined outcome the USDC payout lands within minutes of the final confirmation.

UK Frequently Asked Questions

How accurate are political prediction markets?

Historically more accurate than polls. Polymarket's Brier score on US 2024 elections was ~0.11 — better than 538 (~0.14) and every mainstream poll. Markets aggregate information with real skin in the game.

Can prediction markets influence election outcomes?

Markets reflect expectations rather than create them. Studies show public-facing markets can anchor expectations, but don't influence the underlying outcome. Political markets are information, not advocacy.

How fast do political markets react to news?

High-liquidity markets move within seconds to minutes. A Trump tweet on the economy can shift the "Trump 2024" market 2-5 points before mainstream media has written anything.

Why do Polymarket and Kalshi differ on elections?

Kalshi must follow CFTC compliance — strict definitions, clear resolution sources, US citizens only with KYC. Polymarket operates globally without CFTC oversight — deeper liquidity, but also higher regulatory risk.

Are UK election prediction markets available from the UK?

Yes. Betfair Exchange and Smarkets offer UKGC-regulated UK election markets (seat counts, party share, constituency results). Polymarket also lists UK election contracts with deeper global liquidity. Betfair winnings are typically tax-free for UK individuals; Polymarket profits are subject to HMRC CGT.