Highest temperature in Seattle on August 9?

Platform comparison

Market context

Seattle-Tacoma International Airport’s highest temperature on 9 August is the settlement trigger, and the market resolves off Weather Underground’s **Daily Observations** table rather than the summary high/low. In practice, that means the relevant question is the observed airport maximum in Fahrenheit, with any late correction only mattering until the first datapoint for the next day is published. The crowd-implied 0% YES therefore reflects a very specific outcome structure rather than a generic view on Seattle heat.

Historical context points to Seattle August highs clustering in the mid-to-upper 70s, with the long-run climate normal around 79°F for the airport and recent day-to-day observations often close to that band. The Polymarket event page states that the current leading bucket is 76–77°F, which is consistent with the broader seasonal pattern and suggests the market is pricing a fairly ordinary late-summer reading rather than an outlier heat event. That makes the 0% YES reading easier to interpret as a narrow-bin distribution problem than a strong directional call.

For accessibility, the regulatory frame matters: German **GlüStV** rules can restrict participation if the market is viewed as gambling under German law, while the US **CFTC** has reach where a product is treated as a derivatives-style contract. A “no-KYC up to $1,500” policy usually means smaller-volume access may be available with lighter identity checks, but it does not remove jurisdictional blocking, withdrawal scrutiny, or tax reporting obligations. The main catalyst is simple: the realised airport observation on the day itself, plus any Weather Underground table update before the next day’s first datapoint.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This overview of Highest temperature in Seattle on August 9? reviews the four comparable platforms from a regulatory perspective: which is accessible in your jurisdiction, where KYC kicks in, how the platform is classified by your country of residence. Live probability is the Polymarket mid; comparison columns show regulatory status, KYC thresholds and settlement options for each platform.

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Does Polymarket KYC apply to UK users?

Yes. Polymarket requires KYC (Know Your Customer) verification for all users, including UK residents. You must provide a government-issued photo ID and a selfie. The process typically takes 5–10 minutes via their ID verification provider.

What is the legal difference between Polymarket and Betfair Exchange for UK traders?

Betfair Exchange is UKGC-licensed, meaning UK consumer protections apply and winnings are typically tax-free. Polymarket is not UKGC-licensed — it operates under decentralised blockchain rules. Profits from Polymarket are subject to HMRC CGT as crypto disposals. Choose based on your regulatory preference and tax situation.