Highest temperature in Seattle on August 16?

Platform comparison

Market context

Seattle-Tacoma International Airport will record a daily high temperature on 16 August 2026, measured via the National Weather Service station's official observations. The market resolves to whichever temperature band captures the peak reading logged in Weather Underground's Daily Observations table—the primary source document rather than summary displays. Settlement occurs in USDC against Wundergro data feeds at market close on that date.

Historical August temperatures at Sea-Tac show a median high around 78–80°F, with the station's all-time August record of 96°F set in 1981. The past decade has seen occasional spikes into the upper 80s during heat domes, most notably August 2021 when the Pacific Northwest experienced anomalous warmth. Current crowd probability of 0% YES suggests traders are pricing in a baseline expectation aligned with seasonal norms rather than extreme heat. Comparable markets on regional US airports typically see meaningful probability mass only when atmospheric patterns shift measurably or when seasonal forecasts flag departures from climatology.

Traders should monitor the National Weather Service Pacific Northwest office forecasts issued in early August 2026, particularly any heat advisories or excessive heat warnings. Upper-level ridge positioning and sea surface temperature anomalies in the North Pacific drive summer weather patterns across the region; persistent high-pressure systems can elevate readings substantially. Real-time funding rates on weather derivatives and any unusual volume spikes in adjacent temperature markets may signal institutional positioning ahead of the settlement window.

Methodology

Methodologically this overview focuses on on-chain pricing: Polymarket's live mid comes from the Polygon conditional-token order book and settles automatically in USDC. The other three venues — Kalshi, Betfair, Manifold — sit alongside as off-chain reference points so you can see how the contract translates across regulatory and settlement regimes.

Resolution & payout

Settlement is on-chain via UMA Optimistic Oracle. A proposer posts the outcome with a bond, a two-hour dispute window opens, then the smart contract lifts winning conditional tokens to 1 USDC and sends payments to holders' wallets automatically. No withdrawal fees beyond Polygon gas.

Off-chain venues (Kalshi, Betfair, Smarkets) settle in local fiat through bank-side clearing — faster than SWIFT, slower than on-chain. Manifold pays no real cash.

UK Frequently Asked Questions

What are crypto prediction markets?

Crypto prediction markets are on-chain smart contracts where you buy YES or NO shares on a future crypto event (e.g. "BTC above $100k by year-end"). The market price between 0¢ and 100¢ is the implied probability.

What does a transaction cost on Polygon?

Polygon gas is typically under $0.01 per transaction. A full trade cycle (Approve + Order + Fill) totals around $0.03 — compared to $5-50 on Ethereum mainnet.

Is Polymarket legal in the UK?

Polymarket is accessible to UK traders but is not UKGC-licensed. It operates under US CFTC jurisdiction. UK residents face no domestic legal prohibition on using it, but UKGC consumer protections do not apply. For UKGC-regulated alternatives, Betfair Exchange and Smarkets offer similar prediction-style markets.

Do I pay tax on prediction market profits in the UK?

UKGC-licensed platform profits (Betfair, Smarkets) are typically tax-free gambling winnings for UK individuals. Polymarket profits involve USDC crypto transactions, which HMRC treats as Capital Gains Tax events. Keep full transaction records and report via Self Assessment if gains exceed £3,000 per tax year.

How do I deposit on Polymarket from the UK?

UK traders typically fund Polymarket via Coinbase UK, Kraken or Revolut — buying USDC with GBP and transferring to a Polygon-compatible wallet (MetaMask, Coinbase Wallet). Polymarket's onboarding walks you through the bridging process. Typical GBP-to-USDC conversion costs 0.5–1%.