Highest temperature in Seattle on August 5?

Platform comparison

Market context

Seattle-Tacoma International Airport’s 5 August 2026 high will be the contract’s settlement driver, with Wunderground’s daily-history page used to identify the day’s maximum Fahrenheit reading at KSEA. On the current framing, a 0% yes probability implies the market is effectively pricing the event as outside the visible outcome set, which is only plausible if traders think the eventual airport high will fall below the lowest listed band or that the market has not yet incorporated a live forecast.

Seattle’s early-August climate usually centres in the upper 70s to low 80s Fahrenheit, and recent comparable market inputs have clustered around the low-to-mid 80s rather than extremes; AccuWeather’s Seattle monthly page shows highs near 80–82°F around 5 August, while WeatherSpark’s August history for Seattle records a 24-hour high of 84.0°F in the month’s opening days.[1][2] That makes the tail risk less about a cold day and more about whether a warm, dry ridge pushes the airport into the mid-80s, which is the sort of range that has mattered in adjacent temperature contracts.[14]

For catalysts, the key watchpoint is the near-term forecast path into 5 August: small changes in marine layer depth, onshore flow, or inland heat can shift KSEA’s afternoon maximum by several degrees, and airport readings can differ from downtown Seattle by enough to change the outcome band. Traders also usually monitor any National Weather Service updates, since heat advisories or a sudden change in regional conditions can reprice the contract quickly; a recent example was an NWS-issued heat advisory for western Washington with expected highs up to 85–90°F.[6] In a crypto venue, that means on-chain liquidity, BTC/ETH risk tone, and any broader funding or whale-driven volatility can affect how aggressively users lean into a weather contract even when the underlying event is purely meteorological.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reads Highest temperature in Seattle on August 5? on-chain. Polymarket's quote comes directly from the Polygon order book — the only comparable venue with on-chain settlement. Kalshi (USD, off-chain), Betfair (GBP/EUR, off-chain) and Manifold (play-money) are listed alongside for venue context. Every CTA routes to BTC Prediction, which mirrors the Polymarket order book directly.

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

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