Highest temperature in Seattle on August 5?

Platform comparison

Market context

Seattle’s latest 24–48 hour setup points to ordinary summer warmth rather than a sharp heat spike, which helps explain why the market is still pinned at 0% for an upper-end outcome. Recent forecasts for the city sit mostly in the low 80s Fahrenheit, with AccuWeather showing highs around 80–82°F and Sea-Tac-style daily temperature forecasts elsewhere clustering in the low 80s too.[1][7][10]

That framing matters because Seattle’s August climatology is already warm but not usually extreme, so a result in the mid-70s to low-80s is the base case unless a late surge of continental heat arrives.[5][14] For comparison, Sea-Tac did briefly run very hot during a summer heat event in 2025, with KOMO reporting 89°F at the airport and noting heat-advisory conditions across the region.[16] Against that backdrop, a market priced at 0% is effectively saying traders see little chance of a much hotter-than-forecast day at the airport.

The main catalysts to watch are the timing of updated short-range forecasts, any National Weather Service heat advisories, and whether inland heat pushes further west towards the airport corridor. Sea-Tac is the settlement source, so wind direction, marine influence, cloud cover and the daily sea-breeze cycle matter more than city-centre anecdotes; the airport can run cooler than nearby inland locations on warm days.[6][16] With the market settling on the highest temperature recorded during the day, a late-afternoon warm-up still matters if the morning starts benign.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

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